I’m in the same boat. It’s so frustrating. I also don’t explain myself anymore and just continue to comfort my baby. Let them say what they will and just nod and smile. My dad “defended” me one day with a “she’s just a first time mom she’s gonna do everything for that boy” and while it was semi backhanded I just let it be and they seemed to quiet down for the day. There is nothing inconvenient about comforting my baby. If anything, the other things in my life are inconveniencing my ability to be there for him all the time😩
One option is to just ignore them, or only acknowledge with "ok" and do what you want. I would respond by sending articles from experts stating that newborns can't be "spoiled" and it's actually healthy to hold and comfort them. Popular advice from the discredited Dr. Sears to older generations is probably why so many of their children have anxiety issues now 🙄 I believe in CIO for sleep training if necessary, but doing it appropriately doesn't mean just ignoring them and letting them cry indefinitely.
“That’s interesting but I’m not interested in advice” has been my go to. It shocks them enough to be quiet but isn’t rude and usually they bug off. I got it from ‘ love on the spectrum ’ and I don’t think I’ll ever give it up lmao
I went through the exact same thing with my family and my child's father's family when I had my son. I remember the frustration i felt and quickly learned that they weren't going to understand my perspective or respect my choice with my baby so I simply quit explaining myself. And just simply told them that this is my choice with my child. Eventually everyone left it alone when they realized I wasn't budging on that boundary....Good luck!