In this case, it appears that the DOI actually followed those rules and came to the conclusion that only MS could provide a working solution. Google is essentially saying in the complaint that
a) Their solution meets the stated requirements and the DOI knew about it.
b) It is unclear if Microsoft's solution even meets all the requirements (specifically the security requirements since Microsoft is not currently FISMA compliant and has a bunch of known problems in its exchange server)
therefore the justification for naming Microsoft's solution is invalid and solutions involving Google's product should have been allowed for consideration.
Since I didn't actually read the DOI justification (only Google's summary of it) and I am not familiar enough with the specific regulations that govern this sort of thing to comment on its validity, I simply wanted to point out that "naming the winner" in the RFQ is not enough to invalidate it and is not necessarily a problem if the proper research has been done.
I think the DOI can require that a solution must be compatible with or have the same features as Microsoft's solution.
However, they cannot say the solution MUST be the Microsoft product, and I think that is what Google is arguing.
Then they'd print a bunch of copies of these several hundred page documents up and mail them to IBM, Honeywell, Wang, DG and DEC and so forth for bids.
The guy at (say) DG would get this, see that the Govt wanted a Vax, and toss the RFP. IBM might try a bid, but usually the "Unix" bit would cause them trouble. [This was well before any serious IBM effort in Unix].
Their requirement is a single-vendor, single-source service that can only be obtained from Microsoft. That's naming the winner before you hold the contest.
An RFQ (request for quote) by its very nature is a request for specific commodities from an existing purchase contract, which are evaluated on a cost basis.
In it's simplest form related to IT, a server vendor has an part number for a hard drive listed on the GSA contract. Multiple resellers are able to sell that part. A RFQ is a solicitation that says "We would like to purchase 50 units of part #12345". The reseller with the lowest price wins.