Well, I think this was a stupid, ill-conceived publicity stunt, but I don't think that the baby was in any significant risk of harm, given the circumstances and the obvious talent Steve has around crocodiles.
I agree that lots of babies are at greater risk on the highway daily, and many are exposed to household dogs and cats which kill a few every year. Life has lots of risks, and it is all a question of degrees. I wouldn't feed a croc like that with or without a baby. I would, however, take an infant out in a canoe with me, which is theoretically (and statistically) fairly risky. As a former canoe instructor, I happen to think it would be pretty low risk. We all have to make these sorts of decisions in life, and I won't second guess Steve for his.
On the other hand, I still think it was unnecessary and stupid.