"Rehabilitation" does not change sexual preference: nothing can do that. It aims to make offenders aware of the consequences of their actions and provide them with strategies for controlling their behaviours to keep vulnerable people, and themselves, safe.
It appears that the man in this case has gone against his own rehabilitation, so bleating about a second chance is pointless. His second chance was to be allowed into society by controlling his own behaviour aand limiting his chances of reoffending, and it appears that he is unable to that.
I think that the woman has made a desperately bad choice of father for her much wanted baby, but she's not the first to do that and she won't be the last. Calling for her to be "taken out back and shot" is neither constructive nor civilized, but a vile knee-jerk reaction that makes the poster appear ignorant and narrow minded, which I'm sure he/she isn't.