No, it came from the moment it was announced. Marvel just ignored it, just as they pretty much always do. No one is trying to hide Taskmaster because of backlash. If they were actually scared of it, she wouldn't be in the movie to begin with.
Trump just won. He won the popular vote. The MCU has had some problems recent in terms of profits. It makes sense that might impact advertising . Not even saying this is exactly what they are doing. But when people advertise these movies they do often take these issues into consideration. Movies try and hide all sorts of things. Like Joker 2 making lots of effort to hide it was a musical in many adds. So between the controversial stuff and the fact the character might die early and also a desire to put your more popular characters up front I think all of these things at least cross their minds.