Why do so many people troll and throw their promos

Why? What is the point in that? Why do so many people decide their team doesnt deserve to win and start throwing? Its so frustrating. Just because you snagged most of hte kills as someone like Kha, doesnt make you god. Thats what the champ does. People understand that. If I support I understand that I'm probably not going to get the kills. That doesnt mean I didn't set them up. Its just so many of these guys get a massive big head/ego because they have 10 kills or whatnot, and when the game gets difficult, they decide their team is trash; the only answer here, and start wanting to lose to teach people a lesson. Yes, this is just one example, but damn almighty if I havent encountered this shit far more than I should.

2 of my 3 of my promo losses were completely winnable just pissed down the drain because of situations like that. And those are the guys that complain about elo hell, being stuck, bad teammates. No, you are the bad teammate buddy. A positive scoreline doesnt give you the right to piss a game away, nor does it mean you are the one carrying. I've ended games with 10+ kills and the lowest dmg on the team; the chips can fall like that.

I dunno why this feels so common nowadays. I've played this game a long time, and it damn near feels every other game or 2 someone is actively trying to lose, on purpose. Legit just wanting to throw the game, on purpose. 9 times out of 10 it comes from the guy doing the best in KDA.

Sorry, just ranting. Just annoyed at these players. Of all games to do it, they are doing it in promos.