I already own it Wasted $5
No you didn't waste $5. You wasted $5 about as much as the people who 'wasted' $29.99 for the game when it first came out.
Things come down in price. Sometimes, they come down to $0. For a limited time. To encourage people to come to a platform.
This same stupid cry was happening when they made TF2 free to play. I paid full price for The Orange Box when it first came out, and I'm glad I did. £40 for a collection of 5 games was a damn good price back then, and I have no problems with the fact that it's free to play now. I'm glad I have contributed to the income of one of the most forward thinking, and probably the best games developers out there.