Tone, I think most of us understand MR's intention of the song similarly as you do, and so did her contemporaries. Attacking conformist attitudes was and is a worthy goal, as agreed by most. Nevertheless, the craftsmanship of the lyrics is found questionable, even by Tom Lehrer whose name might well outlive MR's, and who cannot possibly be accused for promoting conformism. (Pete Seegers was not as critical and honoured the good intention and other positive aspects, which is his perfect right as well.)

In a nutshell, the feeling is that the song unduly confuses people who have no better idea or wish - the conformists - with those who see no better option, who may feel insulted.

MtheGM, there is nothing wrong about doctors and lawyers, but everything is wrong about parents pressing their children to those careers for sake of wealth and prestige, and about having that conformist idea of prestige at all. I think we can read this message from MR's lyrics alright, considering it in its historical context, but I agree with you that she should have made it clearer whom exactly she criticizes for what.