@Neo_Chen 99% of cosplay entries tagged "latex" are PVC or just some somewhat shiny textile. Give it up, the taggers here have no clue what they are doing.
Base +8, qq1287860266 +6, grabeuh +13, nnoixa +6, Pätemätön +6
It is clear that neither of you has a fucking clue.
https://ehwiki.org/wiki/latex
The tag is poorly named because "Rubber/Latex/PVC/ect." didn't quite roll of the tongue and these wouldn't work as separate tags because people need to be able to tell the difference on black and white content without being experts on the matter. If you really want to get angry about this sort of stuff just see what happens if you try to tag f:Leather.......
Your best shot is to request a change to it here https://forums.ehentaihip.cc/index.php?showforum=89 but given the reasons I mentioned behind the generalisation still being an issue today and sunk cost fallacy always favoring the current status quo, you'll be unlikely to get a lot of support.