This is a common but IMO not quite appropriate point of view. Are you also pissed of that people bought CoH2+WFA during various steam sales for maybe 20$ (which is not the 100$ less you paid, but almost)?
Sales are one thing, giving away a game after loyal fans were screwed by the most worthless CE of all time is another. They still need to do something to comp the people that paid $40 extra for $5 worth of content. You hardly ever see a paid game go f2p, but giving something as a thank you to the people that actually paid money for it is just common courtesy.