Hmm...interesting. So the thread doesn't specifically mention that AOC is going to waive first amendment rights for hateful speech. All I see is her pointing out that the ad led to death threats, words hurt, and that some free speech advocates are hypocrites. If she does say to the public that she will make the government penalize you for hateful speech, then I'll criticize her then. In contrast, Trump literally said in a rally that he wanted the government to jail Americans who burn the flag for a year.
https://www.forbes.com/sites/andrewsolender/2020/06/20/trump-says-he-wants-to-punish-flag-burning-with-a-year-in-prison/#3959e4ae3404
As for a leftist politician who fights to protect the first amendment, how about Bernie Sanders, the cornerstone of the American left: https://www.huffpost.com/entry/bernie-sanders-ann-coulter-berkeley_n_58fb7006e4b00fa7de14bc3d