I think i found an answer.
Because they're not interested at game at all.
Theres a little bit of silver players who actually care about the game and are trying to improve (dont look at my match history please. PLEASE). But there's the another half, the players who think that this is call of duty, the players that dont even know about this forum or any news about champs etc. Those are the players who are saying 'fk u its just a game' then they go 0/10.. They literally dont give af about your game, your promotions, your rank. For them, its just like another Counter Strike game, get killed, never mind, ill just leave and im gonna join another server without any loss. My friend, for example got placed in silver 5 last season, he plays 1 game in a week and he plays lol only when he has nothing else to do. He fed his way HARD to bronze 5 (i wont mention his nickname). His kda is about 4/12 and has 58 minions of an average. Top laner 'main'.. Those are the kind of people who are feeding.. :D
And please without downwotes. There are the players who are trying to improve but they're having just a bad games, and theres no reason to flame any of them at all. They're just doing what we dont, enjoying the game..