It's just part of the continuum of life. You get judged by your peers when you're growing up, at school, in the workplace... why not as a parent? Trick is to develop a thick skin... accept all the praise, reject all the criticisms, trust your own judgement, don't complain, don't explain..... and apply that to the rest of your life as well.
IME the strongest opinions I've been offered on childcare have come from people who don't have any children, don't want any and would run away screaming if you tried to foist one on them. But that doesn't stop them knowing best. Indeed, I think they believe it's a positive advantage, because they have the outsider's perspective you see.