Do Uber drivers even have an expectation to earn a minimum wage? But to answer your question, yes, I do avoid stores and businesses that are known to treat their employees poorly and e.g. block unionization.

As for "Uber drivers can just quit", I think that's a very simplistic argument. Uber are pricing competitors out of the market (using venture capital!), turning what used to be a fairly decent job into something that's barely enough to scrape by on. The people likely to driver for Uber likely don't have as many options, and probably fewer by the day as jobs that don't require are lot of skills are increasingly being turned into temporary jobs and platform gigs. I'm from Scandinavia, which has a very high degree of social cohesion and low economic inequality, and I see it very mch as a regression and a danger to society.