You are making up risible excuses ad hoc.
You argued that the bloodline had to be kept pure but you forgot that the bible celebrates the pollution by Moabite blood through Ruth. This is a knock-down argument against your apologetics and not surprisingly you totally ignored it.
It is beyond the comprehension of every rational and moral person how it can be good to murder thousands of innocent babies - every single one without exception - in revenge for the actions of their ancestors 400 years previously.
The bible is very explicit about the reason for the attack. You seem to think you know better than the bible. It was in revenge for a trivial incident during the exodus. The bible says so. Own it.
Your apologetics are almost identical to the twisted reasoning of the Third Reich who murdered millions of babies in order to protect the Aryan bloodline.
Christianity leads to disgusting and dangerous ethics. The strongest arguments against Jesus result from watching his disciples trying to explain the moral monster they worship.