In other words, are people allowed to ask questions about the philosophies of the FSF, OSI, CC, etc. from the position of disagreement?
Yes, but ultimately this is a Q&A site that seeks to collect information into a large collection. Questions are free to ask about FLOSS philosophies, and to do so from an adversarial perspective, but must do so along some kind of factual metric, rather than a subjective one.
- For example, "If all software can be freely modified and redistributed, how could software developers possibly make money? Isn't the ability to charge per copy effectively destroyed under such conditions?" is a great question, which could be answered by explaining whether or not the resulting economics would indeed eliminate the ability to charge per copy, plus explain market strategies that would emerge if it did so.
- A slightly more problematic question might be, "How does free software justify the fact that there exist no market strategies that allow programmers to make money for the act of writing free software?" This question is still on-topic, but misaligns with the necessary answer: an answer needs to deconstruct the question's assumption, i.e., free software need not justify this outcome because it is incorrect. This is still ultimately a question of economics, despite being phrased as an ethical question. You might find the economic answer unsatisfying, but even professional economists can disagree widely on the outcome of any particular course of action.
- A very off-topic question might be, "I personally want to be able to deny giving recipients the right to redistribute my software. How does free software justify asking me to give away my legal right to do so, when I hate the idea of doing that?" There is no objective metric here: sure, the asker dislikes free software, but that dislike hasn't motivated them to ask a particularly meaningful or useful question.
An interesting borderline on-topic question might be: "Why does free software focus on software only, when it doesn't appear to be meaningfully different from other intangible goods that can be copied freely?" A good answer might investigate what position the FSF/OSI does have on non-software works like e-books and digital music, and include any justification they provide, for both their views and their level of effort (e.g., possibly they agree in principle, but feel another organization is better equipped to advocate on this matter). The factual component to such a "why?" Q&A rests in discovering what viewpoints and justifications have been offered by proponents of the named philosophies.
Such a format runs the risk of burrowing uselessly deep ("Well, then how can they justify that justification? Oh, but how do they justify that justification, then?") but at a surface level of questioning, I think asking about what philosophical viewpoints exist, and how they address immediate practical problems, is on-topic. You may ask such questions from an adversarial perspective. You may find the philosophies you ask about remain unconvincing even after you understand their justifications more robustly, but that's fine: we're only a Q&A site.
Since you ask for particular instances where this guidance has been appropriately followed, i.e., appropriately factual questions have remained open despite a subjectively skeptical or hostile attitude toward FLOSS:
Why don’t unprivileged user accounts violate the GPLv3?
- This question says the GPLv3 was designed to be "deliberately almost impossible to comply with" for certain industries and pointedly asks why the SSPL is hypocritically treated worse by the FLOSS community despite being more or less equivalently antagonistic. That said, the question is clear about its specific claims and questions, which allows answers to fluidly clarify unknown points and correct the misconceptions expressed clearly in the question.
Does Free Software Foundation's guidance about SaaS disallow usage of password vaults?
- This question prompted a now-resolved-and-deleted discussion featuring one viewpoint, "My problem with the question that on the first spot it looks like a statement. Like 'Did politican X eat his mother?,' this is a not a honorable journalism even if it does not state anything about politician X" -- so it's clear at least some of the community read this question as antagonistic. That is, some subjectively read the tone of the question as "how can the FSF be such luddites as to condemn such a necessary modern tool as a password manager?"
How to address common FOS license problems? - About creditstealing and ruthless cashcowing
- The author openly states their question arises because they "had some disputes with a group of passionate FOSS proponents" -- clearly the question is not based in an endorsement of FLOSS ideology.
How can I trust to Open Source programs?
- The question reads deeply skeptical (rightly so, IMHO, given the problem domain it asks about) but especially in view of their comments, I see this author as intent on proving that their proposition is impossible (which is broadly correct) at the expense of not taking in the useful information in the answers they received. Nevertheless, their underlying factual question is relevant, unambiguous, and reasonably answerable, so the question rightly remains open.
Pertaining to your recent specific question that you've linked to here (which, full disclosure, I answered, and did not vote to close), I think it began as a really good on-topic question, whose projection into the factual-Q&A space I might phrase as "How can free software justify asking programmers to give away their software gratis?" to which I offered the answer, "Economic forces will ensure programmers get paid for software labor, even if that payment does not come from many end users paying per-copy." When this answer (even after many edits directly addressing your specific concerns) didn't appear to correspond in any way with what you wanted, it called into question our understanding of what the underlying factual subject of the Q&A was. In other words, it became less and less clear how one could formulate any answer that was in communication with what you wanted to learn.
I personally think your underlying questions (as I initially understood them: how developers get paid for making a software artifact that is given away gratis to users, and how non-software media is considered under software-freedom rules) are great ones for the site. I would love to get your question back into an answerable, openable state! I am very happy to discuss this further in the comments or chat. (I only ask that you not mention "providing expertise or documentation" as an economic model: that is a separate, parallel, economic strategy that doesn't have anything to do with the economic outcome I propose, whereby programmers get paid for actual development labor. It doesn't pertain to my answer and I'm not interested in discussing it separately from my answer here.)