The other guys have pretty much answered why you get punished, so I'll answer why the other players aren't getting punished;
They are given the same chances at reform as you get. It takes a lot more than 1 game to get punished once, let alone get banned. There are 4 tiers of punishment you have to work through unless your offense is severe enough to skip them. You also rarely see when a person you report is punished (your report has to be the final one that triggers it), and even when you do it won't tell you what punishment they got. All that aside, those are individual players; you can't say "Player A was toxic and I reported him, why am I seeing Player B toxic too?". They do get punished, but there will always be more, so you have to deal with them as they come. When you get punished and they don't, it's because you are more consistently toxic.
I suggest simply muting and reporting. Getting upset and confronting them is exactly what they want you to do. You will never win unless you learn how to ignore them.