That is 1 video, as someone who watches streams and plays daily it isn't any worse then it's been in WOL and in HOS.
HOTS era had the broken infestor/Broodlord builds. The scene atm is better, even Terran has had recent buffs. Only argument you can have is that Terran has been at a disadvantage since HOS, but the current best player in the world plays Terran.
That's one video of many, other streamers like Pig, Vibe, Ruff, Protech have ran into such individuals on stream while some players have live streamed to hacks to bring it to Blizzard's attention unfortunately they can't ban these cheating clowns from the ladder because they stupidly made the game's multiplayer f2p.
Broodlord Infestor wasn't a problem in HOTS in fact the Infestor was a dead unit in HOTS you're thinking of WOL which is almost a decade ago, the current best player in the world plays Zerg in Serral as he's had the strongest record so far but either way the problems aren't just with one race it's with all of them and the 12 worker start. The game is in a terrible state and is frustrating for people on the ladder to play.