Thing is when the adc and support go 0-2 0-2 in lane, and the ADC just basically gives up on the game and does the whole mindless splitpush thing and doesn't really actually try to win the game anymore, This is indeed a toxic attitude.
A couple streamers I've watched who have played on NA mostly but also on EUW and other servers say this is a big issue in NA, for many NA players, if they aren't the ones carrying the game or if they are doing poorly they immediately shut down and stop really trying to win.
One streamer said: "I would rather a player cuss me out and tell me they hope I die, but they keep playing and trying to win, than a player who says 'oops sorry' and has a 'good attitude' but just keeps running it down" And I agree with this 100%.