Recently, anti-Trump folks launched a #BoycottUber campaign. Tons of people deleted the Uber app off their phones and/or deleted their Uber accounts. Many of those former Uber users went to Lyft.
Immediately, I saw the "Are you a real progressive?" purity tests surface on Facebook. "Wait, so are you also boycotting X, Y, and Z companies?" and "You know Lyft has ties to Trump, too." Of course it does. Facebook itself has ties to Trump (Google Peter Thiel).
A lot of people tied to Trump are rich corporate types. So if you use corporate products, you're likely using something tied to Trump. We are in a messy web right now. You cannot fully disentangle yourself without going completely off the grid.
The point of a protest is not to say "I am pure. I do nothing to support... whatever I'm objecting to." You're most likely wearing clothes produced by overworked, underpaid child laborers. You're likely eating chocolate harvested by child slaves. If you can afford to, you're likely paying to live in an area with cleaner water and less pollution than areas where people with less money than you live.
It's complicated. You can't solve all the world's problems through a boycott. And you will never, in the foreseeable future, pass any kind of progressive purity test.
But a progressive purity test is not the point of an effective boycott. The point is to influence companies and to remind them that they can lose a lot of money if they don't listen to their consumers. And you'll notice once you do participate in an effective boycott, the companies usually scramble to apologize and try to make it right with their consumers. They do not want to lose money.
Also keep in mind that even incremental changes can be good. Remember that environmental slogan of "reduce, reuse, recycle"? Imagine if it was "Never use anything or else you're ruining the earth!" How effective do you think that slogan would have been? Yes, people who use gas-fueled cars still object to the Dakota Access Pipeline. Should they not drive less? Or should they just throw up their hands and say "Well, I'm supporting the oil industry anyway... might as well keep driving more"?
Waves crashing repeatedly against a rock will wear that rock down. There is death by a thousand papercuts. And we can, each in our own little way, help to make the world a better place. Beware of the tempting false dichotomy of "I'm doing everything right" or "I'm doing nothing right." Do what you can. You can, for example, reduce your carbon footprint without eliminating it. You can boycott one company and influence it and then boycott another company later. You do not have to boycott all the bad at once—and I'd challenge you, if you think you're already doing that, to dig more deeply into how interconnected everything is.