I agree with the principal of personal boycotts, though not effective in doing anything to affect the companies that you are boycotting, are necessary. But OP is right. For instance I have been boycotting Chick-fil-A for the last 10 years because I don’t agree with their homophobic attitude. But it has zero effect on their bottom line because no one else boycotts them or even cares. I think the kesson is that you should not expect any kind of real outcome from your personal boycott of a company. You should just be satisfied that you are not personally supporting that company.