I'm on the American left, and I really don't see it that way. Not at all. Nothing as profound with dark symbolism as what you described.

Instead, the explanation (if one is needed) is something that more straightforward and rational. I think it's just creative people gently poking fun at Bernie for how he under-dressed for the important event, and that it was odd how he didn't appear to be interested in socializing or celebrating with others... as if he really didn't want to be there.

As you can see in the many memes that have been created, there are so many possibilities with amusing and surprising visuals. This really has nothing to do with anyone being "silenced", alone, etc. No need to make it more than what it really is. Just enjoy it and laugh along with everyone else.

Laughter is good for the soul. (Especially after four years of horror and anger and fear and outrage.)