Why is Dota 2 So Toxic ?

In this Video I talk about How Toxic Dota 2 has gotten in the Last Few months where players will throw games and all chat blaming everyone in the lobby for there bad plays as well as cheaters and boosters in the game , Dota 2 has lost many Players Due to these high Levels of Toxicity , and its sad to see that Valve won't do much about it , other than maybe a few games in Low Prio which isn't much of a punishment , there should be more severe consequences for Players who Grief Ranked Matches or lose double the MMR , something needs to change , Does this Happen to Any of you ? Im sure it does