So in looking at the first link. I had a hard time finding a single example of anyone pretending to be a journalist, except maybe the owner of the twitter account. What I did find were hundreds of videos of random people getting in fights, the owner of the account talking about the fights he had also engaged in, and a lot of claims about people being part of a secret underground antifi something or other. In reality not one of the videos seemed to be depicting anyone supporting or proclaiming that they themselves were antifi (though I’m sure there are a few somewhere in there) but most especially there was no video of evidence of any of the “secret” antifi activity that the owner of the account seems to be selling in his upcoming book.
As for the second post. It is indeed a person wearing a shirt that says press on it who is not a journalist. However, the given reason was “so he would not be shot by feds” which to me highlights the spirt of this conversation, that there is growing concern as well as some evidence that the country has sifted toward a more authoritarian bent.
Edit: I forgot to mention that there were no rocks or molotovs being thrown in any of the videos I saw, which there were reportedly hundreds of.