The Gemara itself says that the father's statement (along with the entire incident) teaches us the purity of the Beis Hamikdash was more important to them than killing. This was a horrible attitude. The Maharsha indeed links this with the Gemara which states that at the end of the second Beis Hamikdash period it was clear that murder was a big problem. I hate to say it, but this is comparable to someone pushing another person out of the way in order that he can have a better look at a certain renown Torah scholar. Sometimes people lose sight of the forest for the trees, and that is clearly what happened here.

Kol Tuv,

Yaakov Montrose