That's not even remotely correct and isn't what the Constitution guarantees. The government can't silence you and that's it, that's all freedom of speech means in America. We don't have any other kind of freedom of speech here other than that, full stop. If a private company like Facebook or Twitter wants to censor you, they aren't violating your rights and you have every right to build a competing platform.
Yes, I have watched more than one Prager U video. While some of the messages are on the right track and could make a compelling argument, it tends to mix in right-wing propaganda making much of what it says a bit suspect. The biggest lie it pushes, in my opinion, is the denial of climate change. You have to be completely blind, ignorant, or stupid to think climate change isn't occurring. The role humans play in it has merits of being discussed, but to outright deny it is idiotic.
They also state the gender pay gap doesn't exist, which just isn't true since there are all sorts of data that shows it is. Like climate change, the reason behind why it exists can be discussed, but denying it exists is ridiculous.
Seriously, Prager U is just porn for red-pilled idiots.