Edit on 22 April to get the fact further up the page: When first writing this I had skimmed over the fact that post #3 described the whole thing back-to-front and has set the tone of everything that followed. The conversation seemed a bit off but I didn't realise why.
So, to be clear:
The Z is being used as a symbol of support for Russia's invasion of Ukraine. Not by anti-war protestors. That is why people are uncomfortable about it being in the game despite it long predating this unfortunate new use.
That is what I was writing from in this post, in contrast to the preceding posts reacting to the incorrect version of what it represented.
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Original post on 21 April:
Context for those who have missed it in the news:
https://en.wikipedia.org/wiki/Z_(military_symbol)
Aside of the overly dismissive attitude you're taking to the conflict itself, this part of your statement is misrepresenting what is being asked for in this context. It's not about removing the letter from general usage at all, but about removing it from this very specific usage as a standalone letter that can be worn on your character as a sort of badge.
While I am not certain if this particular OP is serious, note that they are asking to alter it to triple-Z so it's not even a matter of asking for the letter to be banned. Other requests have suggested Zeta as an alternative, which I think makes more sense as a link to the achievement anyway, and again does not actually remove the letter.
I am in two minds as to whether changing the title would be a good idea. There's some merit in the argument that shying away from using Z in other contexts is just reinforcing the pro-Russians' claim on it, but also in not wanting to keep something that has become a pro-war symbol. But then perhaps making a fuss over it does more harm than good, and the safest approach is to just not alter it when it was created independently.
Edit to add, because I missed saying it as I figured out how to best word things: I think my personal preference would be changing it to Zeta, but I can see why SE potentially wouldn't want to make a big deal of it.