Not for me. Even when I'm zoning with Raven people don't disconnect. It's usually either people brand new to the game or assholes who are top ranked who RQ the most.
What I am saying is, assholes aren't bred from COD, they just gravitate towards it.
They gravitate towards it because it's a genre that encourages it. Did you not see the video above? Shouting and swearing at your opponent aggressively is encouraged and allowed. It's specifically not allowed in fighting games. An environment that encourages anti-social behaviour is going to be worse than one that prohibits it.
And assholes ARE bred from shooters. I've seen the most tranquil people turn into raging monsters when they get into CoD games. Certain environments bring out the worst in people and the shooter genre does that more than any other.
Plenty of people from parents talking about children to girlfriends talking about boyfriends have written blogs and made videos about how their loved ones change and become obnoxious when they play shooters but not other games.
Playing MK online can turn people into swearing madmen but the amount of sheer hate and vitriol in the FGC doesn't compare to shooters.