Its true, in many of the points for which Uber is criticized (including this), Lyft is no better. One might even go as far as to say something along the lines of "there is no ethical consumption under capitailism."

But the point of a boycott isn't to purify one's own ethics, but to get the producer of the boycotted product to change their behavior. To this end it is more productive to focus on the market leader, or the most egregious offender, or some other 'tall poppy' of impropriety, than to try to boycott all actors you believe are unethical.