I think it’s considered a microaggression when it’s used by less-than-well-meaning libs (often parents of trans teens who don’t respect their child’s chosen pronouns) who think nobody will notice they’ve “beat the system” avoiding misgendering by they/theming. There’s also a contingent of the trans community that prefer strict adherence for themselves to the gender binary and are rather sensitive when it comes to discussions of being non-binary or “dismantling the gender binary”. Because of these factors, and more, some people outright reject they/them as general all-purpose pronouns, especially so if their preferred pronouns were previously listed/discussed/etc
Edit: I’ve heard weaponizing they/them is more of a thing on TERF island but I don’t know enough to speak on that
I’ve heard https://www.liberation.fr/ is relatively left but I haven’t verified. https://francaisfacile.rfi.fr/fr/ is good for learners