They're completely anonymous statistics, I don't really see the problem. It's like Microsoft saying "Half of our Windows customers buy Office and 10% of those people buy Xbox games". It's totally meaningless in anything but a statistical context. The hardware survey is opt-out. You're obviously ok with it considering you gave Steam a bevy of personal information to purchase games on the service in the first place, so complaining after the fact seems strange especially considering they don't give away anything to personally identify you.