Also, there is the fact that the site has to make money to keep running. There are bills to be paid every month. CS eggs were being purchased too often with TU and not often enough with cash.
If we want Res to stay around, it needs to bring in more funds, plain and simple. Making CS eggs a cash-only purchase was necessary to bring in more money.
I realize that the eggs will not always be on the market from the cash-paying users, but that is a good thing...eventually, the value of these pets will increase within the game to what they are actually worth. The economy will see improvements, and everyone will benefit from having more TU in the end. =)