In a recent question, a user complained that one of their answers (
10k+ link at the moment; screenshot answer now undeleted, see the answer timeline for more details) was unfairly flagged as plagiarism and summarily deleted.
The OP there has also asked for no further discussion to take place there (though in my view the OP has no such right - they can ragequit if they want to, but they don't get to decide what others can and cannot talk about) and a moderator has closed that meta question (again, completely unjustified in my view, but oh well). Since the discussion there has been shut off prematurely, I'm posting this as a separate thread.
In this specific case, it seems to me that:
There is no plagiarism of the text. There is some indication that the answer text (10k+ link) is indeed based on this page, but there is nothing in the text that I would classify as plagiarism. The answer could benefit from citing the source, if that is indeed the page the OP consulted, but the paraphrased text is re-structured enough that it is clear that they are the OP's own words.
There is an unattributed use of this image. This is an academic problem (always cite your source), and it is not clear that this site is licensed to reuse that image, but this is in no way a fatal flaw in the answer.
The answer contributes content above and beyond the specified source. This is evident from even a cursory comparison, as the image of the Apollo heat shield, and its associated text, is absent from the purported source.
The clear conclusion is that Suzu Hirose's claim of plagiarism in a comment is completely overblown, and at best an example of carelessness when making such a flippant remark.
The moderator action to delete this post seems to me to be completely overblown. The moderator seems to have taken Suzu Hirose's comment at face value, and seems to have thought that the text was taken directly from there, when a reasonable inspection shows isn't the case. The moderator's tone also seems off to me.
The moderator comment, on balance, seems OK - the moderator has expressed displeasure with the answer, and it does fall to the OP to say something along the lines of "hey, read the post again, there's nothing like that going on here!".
On those lines, the immediate deletion of the post seems completely unjustified to me. Deletion could be justified if the plagiarism was actually there, and(/or?) the OP had been given time to respond (and possibly failed to), but this does not tick any of the boxes.
In terms of specific outcomes that I would like to see happen, the answer in question should be undeleted - there is no reason for it to be out of action, because it contains no actual plagiarism. After that, someone (ideally the OP, but they seem to have left) should edit in the image attributions, and probably add the source as a further-reading link, but those are minor problems.
In general, I read this as a localized instance, and I don't think it is representative of a wider trend. However, there's also no harm in asking the moderators to be extra careful, in general, when vetting accusations of plagiarism, to check that the plagiarism is actually there before summarily deleting any posts.