I can also picture a “betrayed by the algorithm” scenario.
The projector was from the speech’s hosts, not the White House. The (ultimately doomed) spokesperson described it as an “A/V failure”. I can imagine someone Googling something like “Presidential seal for Donald Trump” and throwing up this satirical one without double-checking it for accuracy. (Because if you’re hosting a speaking event for Trump, you clearly aren’t the kind of people who value accuracy and careful fact-checking.)
It’s the same way that local TV news sometimes insert a picture of the wrong person in obituary clips. (Measure twice, cut once, everybody!)