Your first example is perfect and flatly contradicts your second. We don't punish the movies that showed people lighting cigs at gas stations when a gas pump blows up, we punish the person who actually committed the bad action. Speech about bad action is totally different than bad action and your attempt to conflate them is shameful.
You just typed a bunch of words into a text box. Did you think, as you were typing, that it didn't matter what you typed because your speech would have no effect? Or did you think that your words might convince someone to change their actions/opinions?
Of course I intended to convince people. What's your point? Adults are responsible (and in particular, legally responsible) for their own actions, not the people who taught them to act that way.
I think that in general, if there are predictable consequences to an action I take, I have some moral responsibility for those consequences. Don't you?
Non-sequitor. We were talking about legal and you jumped to moral. I don't believe that anybody should have legal consequences for speech that doesn't incite violence or libel.
Even with moral, I'd argue that the consequences have to be reasonable. It's not reasonable to take advice about vaccinations from anybody except a medical professional. I eat junk food and I tell people it's delicious. If some of them hear me say it's delicious, eat some, get fat, and die, I don't feel morally responsible - take advice about your diet from professionals, not from me.