Some people have objections due to a variety of concerns relating to the company's behaviour, including recently doing the "making China happy" thing alongside a lot of other big names in the industry. There's also the past 18 months of the Steam client having been a known health hazard (causing issues for people with migraines, epilepsy and a few other conditions) which Valve has not just ignored, but actually made worse instead of better since they caused the problem.