People believe lots of different things. What is inappropriate to say in front of one person is not inappropriate to say in front of another. I believe that given their target audience nothing in the post was inappropriate. The slight but vocal response would seem to back that claim.
To tell you the truth I must be so far in category B that I still don't understand the protest. Man has been used as a synonym for human for as long as I can remember. That would make men being the plural of man a synonym for people.
To be completely fair, the original ad that was referenced really was looking exclusively for males.
But does this mean that we should avoid all references to a past in which people were less enlightened? Must we pretend that the world was never that way, or pretend that everything that happened in that world was evil because of it?
Those who jump on the slightest whisper that men and women, or people of different races, or cultures, or whatever, might be different in some ways are deluding themselves. That's not to say that we can put a value on any of these differences, nor that these differences are any more than statistical tendencies and not applicable to individuals.
