I'm torn on the issue of parting ways with someone over them supporting a despicable person.
On one hand, supporting someone who's genocidal or something is bad.
Trump, on the other hand, might be the exact terrible thing this country needs to reign in government. Lets say he wanted to detonate a nuclear bomb off the coast of North Korea. (Borrowing from the most recent Dan Carlin/Common Sense podcast [0])
This would be objectively bad. We should not be nuking anything, anywhere, ever. Period.
If trump-the-president wants to do this, you might really quickly find people talking about the constitutional limits to declare war that Congress is supposed to maintain.
So, they might step in and say "Actually, presidents cannot unilaterally declare war. Oh, and they cannot create internment camps, or do deep packet inspection on the entire internet, or collectivize businesses, etc."
In other words, when a terrible guy gets into office, everyone else might wake up and try to roll back his power. So, it might be a net win, though it's a hell of a gamble to get there.
So, by that line of reasoning, I could see the GOOD that a trump presidency could bring about.
Even if I couldn't, I still don't know what the limit is for donating money to a cause and forcing separation with a company. The free-speech guy in me says it's fine, but... I really don't like trump.
[0] http://www.dancarlin.com/common-sense-home-landing-page/