Calling someone trash is toxic, yes. Lol, and that's a terrible thing to say to someone. Trash talking can also be considered toxic.
Basically, toxic can be anything that ruins a game and begins to turn into bullying of any kind or negative in terms of behavior.
When your experience begins to ruin another person's experience because of the things your saying, that is considered toxic chat behavior.
As for gameplay, that is a whole 'nother enchilada and is alot harder to address because people have bad games all the time. Heck, I go 0/11 sometimes and its not because i'm feeding/inting. Its usually because I get outplayed really hard by a lane opponent and lose really badly lol. I start falling behind and can't cs because of alot of pressure. I'm not fantastic at the game, and I know when i'm doing poorly. I don't need people on my team to start turning sour and pointing fingers, I need them to stay positive and work towards helping me come back so we can win. Postivity not only makes the gaming experience more pleasurable, it helps win games.
Anyway, I do take all these toxicity subjects about the community personally. That one game should not decide how people treat me and how people view me: it's just one game. And we all get those games, we just gotta que up again and stay a positive force in the community so that we can learn from our mistakes