I suppose that could be considered a very mild form of trolling.

I guess the theory is that Trump's followers are force-joined into subscribing to the Biden White House's videos. So then they react by downvoting every unsolicited video that pops into their streams. And the response is to delete their downvotes? So I guess the message to them is, "You really must look at what the Biden White House has to say. Oh, but you're not allowed to express your opinion about it."

Actually, you are allowed to click "dislike" and to feel like you expressed your opinion about each video, but later we will delete your opinion when you look away.