Flame vs Opinion You Disagree With
I've gotten reported for telling my jungler that he should have helped me push after my laner was forced back from a gank (and I pinged to push as well) because it would reset the wave and let me back faster so I won't miss CS while also making them miss CS. There was no insult or anything passive aggressive. Likewise, I've been accused of flaming for saying that the jungler should focus the mid Vel'Koz shoving me under turret without flash or ult. instead of going for the Gnar who has escapes and summoners as well as less carry potential. Again, no disrespect, just good advice imo based on the game state.
I haven't actually been punished yet but I think it's worrying and rather pathetic that people report just if you give advice or they disagree with you. There's a big difference between flaming and defending an opinion or giving feedback to hopefully have the team adapt and win the game.