Topic: 'Textile' is a derogatory term for non-nudists.
My Take: I disagree. 'Textile' is a useful term that is not inherently derogatory.
'Textile' is a term that nudists sometimes use to indicate people who are not nudists. However, I have witnessed a backlash by some in and around the nudist community who interpret the term as an insult. I would argue that a certain amount of condescension towards non-initiates in any minority group is inevitable, but that this doesn't poison the term or rob it of its legitimacy.
Nudism is a lifestyle defined not only by nudity, but by its opposition to one of the fundamentally accepted tenets of modern society - that we wear clothes in front of other people unless we're having sex. It's perfectly natural that nudists would not only come up with a term to describe themselves, but also one to denote those who do not see the world the way they do. There's nothing wrong with that.
Tribalism is part of human nature, and when people find a group to which they feel a sense of belonging, it's natural to develop some prejudice towards outsiders - especially when those outsiders are perceived as a threat to the group (as mainstream society frequently misunderstands and actively restricts the practice of nudism). But the possibility, or even likelihood, for this prejudice is not an argument against using relevant terminology to distinguish the two groups.
It may be somewhat of a taboo to compare nudism to anything to do with the LGBT community, but I am reminded of the term "cisgender", which was coined to differentiate transgender individuals from those who constitute the majority. Just because some extremists may use the term in tones of derision towards cisnormative society doesn't change the meaning of the term, or reduce its practicability when talking about the difference between people who are transgender, and people who are not.
Sometimes people who constitute the majority resent being "re-branded" by alternative communities in this way. But this is really just an organic side effect of shifting perspective to include the existence of the minority group. Non-nudists are not expected to refer to themselves as textiles, just as non-transgender individuals are not required to identify as "cisgender" in ordinary circumstances. These terms merely exist to provide a useful distinction for minorities to differentiate between themselves and the rest of society.