You’d be surprised…
Obscenities are the most benign scenario… at least in that case some people had a verbal altercation, happens every day in real life while driving around, block them, who cares, right?
However, what about the cases where things go far beyond a few obscenities or when actual crimes can be arranged or committed via the voice chat?
If there are no logs and someone complains or files a lawsuit and you have a “voice service”, but you provide no voice service moderation or, at the very least, a “voice to text chatlog” (which in an of itself would require resources to run, a ToS of its own and some very detailed legal protections) to check those claims or provide the relevant evidence to the law or protect your platform in case of slander, then OGS is fried. Done. Over. Sued to oblivion.
Do you understand the extent of the moderation issue now, @mikhail.trusfus ?
Go google “voice chat ToS” and you might notice that it always goes along with moderation and very often with specifically mentioned recording and log-keeping (and when it is not explicitly mentioned, it is implicitly implied).
If anything of the sort happens here or in the game chat, all that is recorded and can be checked. Similar capabilities should exist for voice-chat as well.
Who is going to code all that?
Where are those things going to be stored?
Who is going to moderate them?
Who is going to pay the laywers to write a robust ToS?
Who is going to be responsible to maintain that system?
…and the monetary cost for all that?
Those are not easy questions to answer and to strut around pretending that they are not even worth considering is, quite frankly, baffling. I could understand the “what’s the worse thing that can happen?” attitude with adding PTT to a game/server back in the day when the technology was new and exciting. But now it is old and tested. We all know what can go wrong and it is a lot of things…
You’d be surprised… They had a recent, very serious, incident in France, if I recall…
I do not often encounter thieves and burglars, but I still lock my car and my door. Did I really need to have a door on my house? 
What logic is this, really?
You do not “care” about people like that… you do prepare against them, though.
Or how far users can abuse an online system… or the legal system… 