I can get it in a way as it is a form of marketing. They already accept a lot of smaller coins besides the likes of BTC, ETH, TRX, … so why not go with the hype and add TRUMP coins as they will probably make some money out of it.
i don't think they made any money. don't forget they needed to provide the bankroll for TRUMP coin, so depending on the time they bought, they could be at a significant loss since the coin is down almost 80%.