OpenSSL FIPS certification (#1747) is for source code, not for binary. This is highly unusual indeed, but it is not the case that only binaries can be FIPS certified.
On the other hand, you can't change the source without losing the certification, so it doesn't actually matter.
I think the GP is talking about a trusting trust attack on OpenSSL: Change the compiler to compile OpenSSL differently, rather than change the source itself.
I guess it begs the question (FIPS mode seems to fail the "talk to a cryptographer rule"): why don't/aren't sec folks more involved to assure standards are meaningful? Was this a NIST-driven process or was it open to public comments?
On the other hand, you can't change the source without losing the certification, so it doesn't actually matter.