They were already shitty in the past. Their stellar return policy was ordered by a court and not of their free will.

Steam has actively engaged in price fixing that has ensured no other store front can offer games for less even if they could because of less overhead.

Not only do they meet the definition of monopoly by controlling over 70% of the market, they have engaged in monopolistic practices.

They are not the good guys. They just happen to have a decent product and a lot of goodwill at the moment.