You've just misunderstood what freedom of speech is. The government won't jail you for your opinions. You can say whatever you want that isn't a threat or call to violence.
Let's be real though. That's why people get to call you names when they disagree with you. They also have that same protected speech.
Protesting is a thing you are doing while exercising your free speech. However, you can be doing 2 things at once. Exercising your free speech while committing the crime of trespassing, etc. That one right doesn't make you legally immune to anything else you're doing.
Of course, people commit crimes while protesting to give their protest some teeth, and in some cases to bring attention to the law they might be protesting. But you should be prepared to be fined and arrested during spicy protests. People sitting in the road acting shocked they get hit and dragged away just make me feel like I'm looking at too many shocked Pikachus. You should expect it. That's why you are there. If you didn't face violence you aren't really showing how strongly you feel. That's what it means to stand against opposition.