On the GFCI issue, you are correct. No sink, it's not a bathroom. But, GFCI's are cheap, so no harm done.

As for the oven, "overfusing" would depend upon the size of the wire feeding it. Assuming #8 or larger, I don't see a problem there, either.

You're not the first to have had issues with HI's. You might be diplomatic, and ask the bozo to check out some HI web sites, for some "clarification."