Why are people so negative these days?

So today I play a normal game. Just when my team is not doing well, our yasuo said "ff at 20!" Then no matter how hard I try to encourage my team for being positive about this and play on, they just won't stop flaming each other, and me too. Even my friends who quelled with me started helping the negativity. In the end, the yasuo who started the flaming and the negativity wanted to report me for NOT GIVING UP! Is this a joke? I know that I'm bad, and I died too much, but I'm getting blamed for being positive and having a good attitude? I did mute them in the end, I just couldn't keep this up. This have happened to me for about 70% of my games. What have happened to this community? Can we just listen to Lux to "Stay positive?"