Well, we can also look at their other games for this. For example, in Dota 2, everyone has a behavior score, based on reports and such. This is used for matchmaking on top of skill, and lower behavior scores result in certain restrictions (like can’t speak, can’t ping as much, can’t play ranked, can’t pause).
This has improved further in recent years, so you probably weren’t seeing how it is now.
It may be different in other regions, but I see significantly less toxicity in Dota 2 compared to Counter-Strike, the only other big competitive game I have enough time in to compare it to. Though my CS experience was longer ago, and they could have improved things there, too.