Sure, some people are talking about the former but are genuinely mixed up about the latter.

What do you feel would be the good-faith way to respond to such people?

Surely it's not by sidetracking into pedantry about the law, which at the end of the day both they and you know that's not what they're really fired up about.

I think that any reasonable person who is just misinformed is going to understand, possibly after some time if they are the sort who find it hard to admit they are wrong. Otherwise, if they are going to try and claim that "No, constitutional 'free speech' means I can say whatever I want without consequence from ANYbody" then I don't think there is a good-faith way to argue that.

Anyone who is "fired up" about free speech but feels that their freedom of speech is being violated by someone other than the government has an explanation to give.

If the explanation is that they feel that other people have an obligation to listen to them, then I don't care.

My freedom of speech includes the freedom to reject other people's speech. If they can't tell the difference between a disagreement and suppression of speech, then that's their problem. The generous interpretation is that they don't fully understand the issue. The realistic explanation is that many people value their own freedom of speech over the freedom of others to the extent that they view disagreement with their views as an attack on their right to hold their views.

Essentially, "freedom for me but not for thee", and I don't rightly care about what enemies of freedom are "fired up" about.

But at the end of the day, much of what conservative "free speech" protests against big tech have been about has been that big tech drew a line on things like violence and hatred of protected classes, and conservatives don't like being told that their ideas, while legally allowed, are not welcome in polite company.