I have a feeling NileRed's senses may be dulled; he also made some of the world's worst smelling stuff and didn't get much from it.

He made military spec latrine odor and didn't think it was that bad. He's built different.

Well not so much built different as "permanently damaged his senses"

Its semi-common in chemists. Unrelated note: concentrated formic acid does indeed kind of smell like an ant sting, and dear god does it hurt.

He also permanently damaged his sense of smell/taste, so I feel like he might not be the most reliable source...