For more than 12 years, there is a code preventing enabling any hardware optimizations in FIPS. I just talked with Stephan, that there is no reason to exclude hardware optimizations in FIPS as NIST now allows hardware optimizations:

https://github.com/gpg/libgcrypt/blob/ccfa9f2c1427b40483984198c3df41f8057f69f8/src/hwfeatures.c#L216-L217

This code snippet should be just removed.

I do not have more information at this moment, but I will update the issue when I will have more.