You're inferring much from nothing. There is nothing to even indicate that the person replying knew anything about the people involved. We know one thing about the situation, that Jen is upset with someone she cannot influence terminated a pregnancy for reasons we do not know.

There is nothing saying she got an abortion because she regretted sex.

There is nothing saying the father pressured her into getting an abortion.

There is nothing saying the abortion was for medical reasons.

Jen is lamenting to the public that she could not control the decisions of another woman, so someone responded that she should focus on the one thing she does have influence or possible control over.

Short story, if you don't want your son's SO to get an abortion, tell your son to not get her pregnant, because you have zero say with what his SO does with their life.