you can go that route, be the 'bigger' person, attempt to reason and explain to people like this that their comments are inappropiate and hurtful, try to take the higher ground and be forgiving, allow them second chances, 'kill them with kindness' as you say. yes, you can do that...BUT some people like this actually, and many times secretly, enjoy doing this to others. I tried this route in the beginning, dh did too, got into the act and spoke on behalf of us both, until that too wore thin. I tried the sitting down for pow wows and explaining my feelings in a sane, calm manner, in some feeble attempt to salvage the damage that was already done. unfortunately the verbal and emotional abuse continued, if not escalated, since now it became fuel for my mother's fire. she actually made the comment, "I know how to push your buttons", and giggled about it. oh, such a clever, BITCH!
if you still think you want to give them that much room, that you have the emotional fortitude to endure more from them, try it, but don't be surprised if it continues, or even gets worse. many times when people get called out for poor behavior, they will twist it around into being YOUR issue and YOUR short coming and YOUR inability 'to not be so uptight' 'over some simple remark' for instance. really, if someone acts bad, says bad things without a thought, it's a deeper reflection of their character and you have to really consider if that is worth your effort to go up against.
and like BBG pointed out importantly, now you have to remember it's not only about protecting your own feelings and emotions, but that of your children as well. AND verbal and emotional abuse is just as damaging as any other, physical, sexual, yet still in our society that gets swept under the rug more often than not. which is tragic in itself. you may feel that you can endure snide remarks and 'protect yourself with an emotional umbrella', but will your children be equipped from a very young age to be able to do the same, if/when exposed to this type of family communication?
I know it's real hard to distance yourself from people that ultimately one should never have to, but sometimes it is the healthist way to handle things.
it is what we HAD to do finally, and I am sure we are the first or the last to have done so.