Why so many people playing Riven(and other skill cap champions) are toxic

While bashing my fast against loss after loss playing Riven, trying to learn a new champion. I noticed something, the urge to be ANGRY! TOXIC! MAAAAAAD!

Not because of the champion however. Because of the players in this 'community'. Obviously learning a new champion takes time. If it is a champion who has a complex or difficult to understand skill set then you are bound to screw up. A LOT!

Now the thing is, messing up is fine, every does it. I've had some shit games playing Riven, and a couple good ones. But what has been bothering me is: "fucking riven pice of trsh can't even lane!" "Stupid wh*** riven fckn sht think they are boxbox." "rivn u r just the worst thng ever." "riven worthless XD" "pos rivn." And of course

? ? ? ? ? ? ? ? ? ? ?

I have a feeling by the time I get even slightly good at this champion. Which champion GG suggests is 70+ games to learn the basics. I will be one bitter, angry, tired human being. In my... maybe... 25? games as Riven, I have experienced more toxicity aimed TOWARDS me than I have with ANY other role or champion I have played since 2011.

Literally people boot into the game, assuming I am a pos inhuman trash. And every mistake I make on this champion, and on my 2 games as Lee Sin. Is turned into a bigger shit fest than I get if I PURPOSEFULLY didn't shield somebody on Morgana.

Is being Toxic ever justified? HEELLLL NOOO! But that is towards ANY player, including ones who are fucking up, trying a new champion or playing badly. Do I now understand why players are toxic on these champions. Yep... I experienced the same on Vayne back in S2, I just didn't realize it at the time.