I think we are overly concerned about what happened in the past. We can't change it, the only thing we can make sure is to think before voting and make sure mistakes don't happen again.
@Sayle can we just take them under our protection instead of as spoils, should we choose to take the second option? Also are all the men killed already, and what happens to the boys?
I'd assume young boys are included in 'children'. This wasn't root and branch cleansing, just killing those who fought (basically all the men). You could take them under your 'protection', but politically independent they're unlikely to survive.
It's not like the cultural assimilation of non-Numenoreans isn't a proud tradition. Elendil didn't take Arnor and Gondor (which includes Rohan) by either being nice or by just populating it with the people from the three ships out of Numenor and minor Numenorean ports.