I'm kind of surprised that this seems to be an unpopular opinion around here, since I've always thought of Lemmy as being pretty leftist as opposed to liberal/capitalist, but there seems to be a base assumption here that voting with your dollar and trying to purchase the most "ethical" thing through the most "ethical" channels is worth the time and energy.
To me it has always seemed intuitive. I mean, what is the goal anyway? If the goal is to destroy the company you hate and replace it with the one you like (which btw you won't, for many reasons), you're doomed from the start because capitalism is gonna capitalism, and that brand you like and think is more ethical is at the end of a day, still a brand whose primary purpose is to make money, and they will put that above all else. If the goal is for the unethical company to make a smaller, more specific change, you're also doomed because the company you're silently protesting has no idea why you've stopped spending money with them, and likely doesn't care so long as others continue to spend.
To me, it seems more about making you feel good about yourself than bringing about real change. Which is further supported by the hostility that often comes with ethical consumerism towards people who don't engage with it - people who fundamentally agree with them but who apparently must be shunned for their purchasing decisions. Obviously I'm all up for humiliating Cybertruck owners or whatever, but there's a limit (looking at you, anti-Brave thread that pops up every month or so).
This brings me into the other problems with ethical consumerist rhetoric - it takes an inordinate amount of time because you have to research every company you engage with in every area to find the "most ethical" one, whatever that means, as well as the subsidiaries of those companies so you can recognize them in the wild. Many of these companies are monopolies or oligopolies and actively try to hide their subsidiaries. This time could be better spent toward much more productive activities that actually have the potential to bring about change. "More ethical" products also tend to be more expensive, and for this reason low income people typically can't engage in ethical consumerism. This money is likely also better spent donated toward organizations trying to bring about real sociopolitical/economic change.
I also draw a distinction between "vote with your dollar"/"ethical consumerist" rhetoric and well-organized boycotts with specific demands because these types of boycotts have actually been effective in the past, and it makes intuitive sense why. When you have a lot of organized people who together have lots of buying power asking for one specific thing, with the carrot of "if you do x specific thing, we will come back and start spending again," rather than the vague ethical consumerist position of "you're not ethical enough for me," all of a sudden it makes good financial sense to the company to make that specific change. The successful boycotts I've seen in the past have met both of these criteria.
Sorry this got to be so long and sorry if there are errors in it, I just kind of word vomited.