I think Ranked isn't as shitty as people feel like it is... but I don't feel like the video did a good job of explaining why.
Throughout the video Sunshine claims that
"Ranked is perceived to be worse than it is because of herd mentality."
With the sub-text being it's not more toxic than normals. We just repeat ranked is worse over and over and it becomes part of the community's psyche.
He then later says (at 2:12)
"Honestly, we can't tell, there aren't statistics"
Boom. Your argument is now MUCH worse. Because at best you are appealing to truthiness
"the quality of seeming or being felt to be true, even if not necessarily true."
As in
"Yeah... people do share bad experiences more than neutral experiences more often and people tend to repeat things enough times and then eventually people will feel like it's true (ie. ranked is worse)"
Because immediately I can respond with
"Well, doesn't it feel like ranked would be more stressful than norms - there is more on the line and people have certain expectations above and beyond norms. Stress and frustration leads to toxicity, so doesn't it make sense than ranked would be more toxic than norms?"
Boom! Now I appealed to truthiness and we're bad to square one.
The problem isn't the perception of ranked, it's the notion of "everyone is out to hurt me" that goes across all of League of Legends which Sunshine briefly touches on at the very end of the video.
I was a plat v support main for a couple of seasons. I'm not particularly great at this game and for the longest time I averaged 150ms ping (thank you NA server move). The only way I won was being a mediator and consensus-maker for my team. You'll never convince a dude who doesn't want to win, to win. Those are lost games, they will eventually become meaningless as the amount of games played approaches infinity. But the dude who so badly wants to win that flames his team because he needs to vent his anger and isn't able to in other ways, those are the people you can lead to victory, because your goals are the same.
Shutting down at the first sight of "toxicity" is how you not only lose more but make ranked (league) seem worse than it is. It's all perception, League of Legends is only as toxic as you see it.