Isn't that voting based on perceived quality of product (which I don't believe is in dispute) rather than an ethical objection of some kind?

Yes, but a vote is a vote. Why people vote the way they do is irrelevant. Certainly, it's hard to get people to count business ethics as an economic factor, but clearly some do. My supermarket is full of products touting themselves as cruelty-free, or additive-free etc., and the number only seems to be growing. It's a slow process, but nowadays sustainability counts for a lot more with consumers than it used to do.

It's different when you're choosing whether or not to directly be a customer of a company.