The voice acting in those Glitch Productions shows sounds "theater kiddish" to me for a reason that’s hard to describe. Every other online "voice actor" these days also has crap acting on the same level. You’ve seen those unfunny Smiling Friends OC videos, they’ve got shitty Glitch Productions-level voice acting too
https://m.youtube.com/watch?v=3u-R4DErat8
This kind of acting is also prominent in indie games and it pisses me off too.

The goated cartoons I grew up on like Ren & Stimpy, Powerpuff Girls, and Dexters Lab didn’t have shitty acting like this.