Desdo

And unfortunately, every time I see a dead hard, I'm about to down the survivor but they use it and make it to the next pallet and it extends the chase to 30+ sec minimum.

Same issues here, although I have 1500hrs. I tried to play without slow downs and I only faced strong teams with the best perks in the game, almost everyone had deadhard of course. I hope the hours ingame doesn't affect MMR because if it is then I am stuck playing only against tryhards survivors...

to answer your question, it's the same reason why strong perks and addons are limited during tournaments I suppose.