If it can't be heard, when the rest of the instruments are playing ... I'm not sure I understand what this guy is complaining about.
Could be he just thinks he has to take it out, regardless. We have a producer here who is "reknowned" for his "attention to detail" and really, he's just like this-- obsessive over every small thing that didn't come out of a pickup or a tone generating apparatus intentionally.
And people seek out his services and pay him a good fee, because it's this that they see value in. If he's that obsessive, sending out long lists of timestamps to his clients to let them know every bit of cleanup on aisle 12 he's discovered he needs to do, he must be good, right?
Again, it all sounds sterile to me and I would avoid him, but I think there's a certain mindset that thinks the more someone gets involved, the more you must be getting from them. Producers and engineers working at the local level in relatively small towns aren't making records for big name acts; they're doing things that they think impress the average person cutting demos and small pressings. And being able to send impressive lists of all the things you found to fix impresses some people, I guess.
Other than this, I don't see a reason for it unless the sounds really are obtrusive.
Don't get me wrong; I go over my own productions with a fine toothed comb, but not everything gets removed, I would usually only completely remove something that's sitting in dead space.
Some things just get driven down to a level that sounds human but not messy - like some of the breath and string sounds. I generally don't remove most of that because it takes the person out of the recording, which is not what I want. I hire session players because I want it to sound real.