@assman162 You're clearly underestimating good authors there. One-punch man is a parody regardless and is labeled as such but chainsaw is not a parody, it's a meta-manga : which means it's a manga that talks about manga (the medium itself and thus other works ), in that case the shonen genre. It's not labeled as such because it'd be too hard to understand for most and as a shonen you'd get more sales selling it this way while still being praised by other mangakas in the process. Fire punch was really interesting and had thoughts into it compared to all the manga without substance we're being fed. Well if you read it carefully you'd understand that it's the author being cynical about the shonen genre, and genre labels in general (which is exactly like you pointed, it's not labeled as such but if a work could be reduced to its demographics, only its themes or genres then it's a failure regardless because it wouldn't have style in its literary meaning).
The author might also play with his characters to show its reader his own condition as a mangaka. Netherless, "slave" corporates or other expressions are fairly common in Japan, especially people killing themselves by working (
Karoshi = overwork death).