The difference is so obvious that I have to assume you also see it. What point are you trying to make then? You believe that if YouTube did not comply congress would fine YouTube or slow down its traffic in the US?
in my opinion it's far worse, it's a flagrant display of extra governmental soft power the likes of which would not be symmetrical for the opposing party.
Sort of... The feds usually drop hints before cracking down with a heavier hand, and I don't think this is that far removed from it. So there's a bit of an implicit threat.
Even if you disagree with that assessment, however, it's worth noting that the 1st amendment specifically bars congress from making law which would infringe on freedom of speech. So, IMO, it's a bit improper for them to write pseudo-official letters asking for censorship.