Maybe this is where the argument is coming from - I’d hate that sort of atmosphere too, but I loved taking DS to sensory classes which were more like what your friend wanted. So somebody saying “all baby classes are a waste of time and just for the parents” would seem like a killjoy to me, because what I am envisioning (quality time with your baby) and what you are envisioning (Instagram) are so very different.
Agree with you.
I think at some point the line is crossed from "this is something that is age appropriate and beneficial for the child" and "this is something a child might enjoy, but probably no more than many other things, and it's more about the adults making a statement about what sort of parents they are than it is the child".
For me, we chose not to do birthday parties for 1 and 2, but know some friends who did because they have extended family over. I'd never in a million years think my friends were all about the adults.
I do look at excessive parties for children that age with expensive custom cakes (for the obligatory photo), the cake smash (again for the photos and everyone else does it on social media), the balloon arches (terrible for the environment, not exactly safe for young children, but at least you get nice photos), and everything is all set up in such a way that it's fairly obvious that it's about the image the parents want to create. Will a 2 year old have had fun? Probably. Is it any more fun than my friends' 2 year olds? Probably not. The party was all about the parents.
Same with the stress I've seen people get into over making sure they're in the ticket queue for the region's most extortionate Christmas events. I'm sure their DC has a nice time, but not convinced it's any more of a nice time for a pre-schooler than many other things, and certainly wouldn't be worth the stress to me.
There's a lot of keeping up with the Jones' I think and one way people justify the stress and expense of things is to act like it's offering the children a better experience.