I don't think Apple (and other companies) has returned because they want to advertise there, I think all major tech companies have been notified of what they must do to 'kiss the ring'. This is like Disney removing the context warnings before some of their older movies. There's no way that the Disney company decided all of a sudden to remove them without external pressure from the government. These companies know that they can't fight this administration because they own all 3 branches of the government. The days when Microsoft could outspend the government in court is done, because now the president can just write an executive order. Congress doesn't even need to pass laws, but if one is needed you know they'll do whatever the administration says. And sure, companies can sue, but somehow they'll always end up with a trump-friendly judge.

Anyway, all that to say that I do believe that corporations are evil and suck, but I don't think this was actually a marketing decision.