Trump supporters are unattractive demographics for advertisers because they're overwhelmingly old and rural, advertisers want to win over Gen Z and Millenials who are going to pay for decades, and not to mention the US is not the only, or even the primary market for most of these companies and being associated with Trump is particularly abysmal everywhere else.

If you want to market to cosmopolitan, affluent, educated and diverse urban consumers, which everyone does, associating yourself with Trump isn't exactly a winning strategy