No, it doesn't make sense for a business to be used as a vehicle for sharing personal views and Gumroad is showing us all why you should just stick to business. It is also incorrect to get bullied into making a statement when you previously did not intend to in the first place. The same repercussions apply.
If I understand you correctly, your logic is that Trump is definitively a racist (something that can't be proven true OR false), we shouldn't examine the nuance of that extremely huge accusation, but we can safely conclude that anybody who supports him is also bad and try to shut down their business. Not only is this lazy thinking but also an easy scapegoat to justify all kinds of illogical actions and unfounded discrimination, kind of like what we are seeing now.
What's your evidence? At what point has enough been done, if it ever can be? After decades of government meddling, affirmative action, diversity quotas, and all kinds of media uproars it is clear that companies not only do not play an important part in solving these issues (as evidenced by how bad things are now) but have in fact been detrimental by inserting themselves into conversations that divide their customers (the people) on issues completely unrelated to their business.
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For what it's worth I appreciate that we can have these discussions without malice and thank @Adam for providing a well laid out platform for them to happen.