Man I'm sick of the phrase "optimizing the fun out of it all", it's so often flung around just to attack the entire concept of a game having advanced techniques and a high skill ceiling, even if the people executing said advanced techniques and playing high-level are having fun doing so, because people enjoy improving at stuff, you know? There can be a discussion about whether a game's designed well enough that high-level play is fun to play, but that's never what happens, it's just people complaining endlessly about "tryhards" because people are playing competitively in a competitive game
His claim of "this is how online pvp games die" isn't really based on anything, and he even says this is happening to Deadlock which is really funny considering its numbers just keep going up and the game has been getting loads of praise
The whole "the game isn't even released yet!" thing is always especially funny because like, if you really think that this stuff is a problem, surely you'd want the devs to be aware of that as soon as possible so they can fix it before the game fully releases? Closed alphas don't exist just so you can have fun, the point is to playtest the game
There's also already a solution for the stated problem of "tryhards playing too good making it impossible for casuals to play", it's called SBMM, but usually the people who complain about stuff like this hate SBMM too for silly reasons
Also, I took a look at that guy's profile and he constantly makes racist posts and calls people slurs, typical gaming YouTuber lmao