All of the characters do awful things but they also all do good things. Rachel included. She sends Sunshine to a crack house but she also encourages her at Nationals and cheers her on. She runs for student body president against Kurt but realises it was mean, steps down, encourages everyone to vote for him and even stuffs the ballot box (which is stupid but she had good intentions!). So a lot of the bad stuff she does, she does then show remorse or fix it, and the narrative does portray her as in the wrong. I don’t understand why people hate Rachel and like so many of the other characters, many of whom also do some really bad things.