Uber, Lyft, and taxis don't just use subsidized infrastructure, it puts additional strain on that infrastructure compared to even single-occupancy vehicles. Uber cars circle around already heavily-congested roadways looking for fares (See: https://www.nytimes.com/2017/12/26/nyregion/uber-car-congest... this creates congestion.

And of course, anecdotally we've all driven behind an Uber car that suddenly pulls over to the side of a traffic lane to let its fare out.