I think that it is important to keep a few things in mind. If you have ever actually looked at what Steam does, there is a VERY LARGE margin for profit. They sell Video Games. They sell Digital Copies of Video Games. There is no shipping/receiving department, there is no packaging, there is no physical product. In fact, getting to the nuts and bolts, we are only buying a COPY of 1s and 0s. Obviously, there are maintenance and salary and other fees involved, but my point is that when a company such as Amazon sells Steam Codes, where do you think they got them from? And do you really think they could have bought 20,000 Steam Codes, at whatever discount, and Steam would not be making at least a small profit? No, both Amazon and Steam are making a Profit on every sale they make. Every. Single. One.
Now, I love Steam, I think that they are the greatest gaming company out there, only second to our own GOG. However they are a business. They hire people, and when those people either A) Serve their purpose, B) Disagree with the direction that the company is going in, or C) they step too far out of line, they have to fire people. That is not evil, that is not wrong, it is just business.
The bottom line is that no matter what the reason is, Steam let 25 people go, and the other 300+ employees are still working on whatever secret projects they have yet to announce. Gaben already told us that the direction, and overall plan for the company, is unchanged. That means that whatever this was, is minor.
Also, if they left on good terms, then they will be able to find another job pretty easily. Think about it: Two interviews, one guy says: "I owned my own company for 3 years." The second says: "I served on the Design Team for TF2, HL2:E1 and E2." My decision would have been made up right then, so long as his reference is secure.
TL;DR: Steam fired people. They will be just fine, both Steam and the people they fired. Move along, Move along.