freedom of speech is good!
but it gets more complicated when you have private companies in the mix, and gets more complicated when talking about things that violate community standards or laws
for instance, when bolsanaro puts out posts and ads targeting supporters of his political opponents that have the wrong election date on them, is it bad if Facebook and Twitter take the posts down? I certainly don't think it's bad. the companies aren't obligated to host things they don't like, that's part of their freedom of speech, and it's harmful to democracy for a politician to just lie
aside from obvious things like CP, you also have doxxing, harassment, ******* threats, death threats, holocaust deniers, vigilante gangs using online platforms to organize violence, nazis, etc etc
on top of all this, no government anywhere in the world (except maybe China) has wanted to actually make legislation around this topic, and they've left it completely up to tech companies, who I assure you do not want to be the ones deciding what's acceptable free speech. they just want to get users and sell ads.