I don't think toxicity is built in, though I understand where the thinking comes from. I play Overwatch (albeit on PC) and pretty actively use a mic, and I make a point of being the first person to talk in a channel. I'm friendly and I'm even-keeled about it, and that sets the tone. Once that tone is set it's very difficult for your garden-variety douchebag to start mouthing off.

The LFG system also helps.