Is it just this particular flavor; or is all emotional labor abhorrent dishonesty(and is it abhorrent because he is willing to do the job despite not feeling the love; or do you find the fact that he claims to exhibit minimal emotional attachment despite doing heavy child care creepy)?
I doubt that this particular plan is going to end happily(maintaining the deception in the long term is going to be problematic; and the news probably won’t go over well); but the condemnation seems pretty harsh for someone who pretends to be someone who doesn’t actually exist specifically at the request of a client who wants the role filled(unlike a catfishing scammer or the like).
It sure sounds like everyone involved here would be better off if they could/would admit that the family just wants a male nanny; but the ability to be markedly nicer to strangers’ children than you would want to be is typically treated as a heroic virtue in things like elementary school teachers.