boycotts are a useful tool in concert with an organized political movement (like BDS or a union of striking workers) but can be ultimately counterproductive on their own:

In short, a strong belief that ethical consumption will lead to ethical practices is not warranted – purchasing as voting is a weak feedback mechanism at best and there are other actors who are able to influence the system. The danger, however, comes in believing that this mechanism can make substantial political change. Ethical consumption gives the individual the illusion of contributing to progress; of “doing their part” by making purchasing decisions. This illusion can detract, and probably has detracted, from trying to put forward an avowedly political agenda that seeks to mobilise people collectively to make the changes they support. Instead, it individualises ethics, it individualises politics and it reaffirms us as consumers rather than citizens – it is a part of the profit-maximising, pathologically-externalising neoliberal market system that has caused many of the problems ethical consumerism seeks to alleviate, rather than being an alternative.

from The revolution will not be bought: Ethical consumption is seductive but dangerous to the values ethical consumers seek to promote