Ok you are reaching here. Trump isn't going to be personally registering his domains. Now you think he has a team or contractors to maintain/build his web properties?

If it's a team, then maybe he tells them "don't use GD". However I doubt it. Here is why, that domain was more than likely bought from a domain reseller. It's easier to transfer domains in a person to person via the register it already is registered at. You can easily move it to a different register once in possession. So they would have multiple accounts at many different registers anyways for this purpose.

If a contractor, then same applies, but I seriously doubt DJT is that petty. In fact, I doubt he gives a flying fuck who registers his domain.

And honestly, GD does do domain registration and management well. The rest of their services are dog shit however.