@anonymous... There's pretty much no way to criticize someone's parenting without upsetting them that I know of. How a person reacts when they're upset? Depends on the person. It sounds like you've spoken to your son & his wife about their drinking several times and it has progressed, from the polite laugh off, to flat out dismissal, to now they're starting to lash back at you.
I would honestly suggest dropping it. Not because you're useless, or to stop talking altogether, but unless they're brain damaged they get that you have a problem with their drinking & parenting by now. No matter how nicely you phrase it. You disapprove of them, but you have also made offers of assistance. They know you're there if they need help. Continuing to badger them? Is only going to result in more blowback. They've said no, repeatedly, and you're not respecting that.
As far as the Q as to whether I've had things about me thrown at me, or judged? Absolutely.
Especially in areas where there is a perceived "best". Whether that's parenting, lifestyle, work, health, appearance, punctuality, etc. Sometimes those accusations sting, sometimes they're like a punch in the gut... And sometimes they make me amused, or flat out fall over laughing. Usually depends on how secure I am, myself, in my choices. But some days it's just the straw that breaks the camels back, or I happen to be having a fantastic day and no amount of other people's issues with me can touch me.