I think it's about what different families prioritise. I read to DS as a baby and only because he had no choice! When he was big enough to choose to pay attention he chose to pay it elsewhere...quite disheartening as an English Major!
On the other hand, I prioritise swimming lessons in babies as young as 3 months and for me there is no option, it is just what I have to do for my own peace of mind and to optimise cerebral and physiological development. Many others do not and I don't get it.
The difference is that whilst I openly do not understand not prioritising swimming and water skills in babies and children (because I can see direct links between swimming and other skills my boy has), I don't scorn those who don't. What I think of their choice doesn't matter anyway, it won't change anything. Same if I hear someone make a comment about something I'm doing - none of my business what people say about me behind my back
And I find I can also be great friends with mummies who choose to prioritise other activities over swimming, and they can get over the fact that I don't prioritise reading (anymore!)
One good friend does lots of reading and indoor leggo-type play and her boy needs to do catch-up movement classes because she prioritised cerebral workouts over physical ones. I am finding that by giving DS plenty of physical outlets, it is helping the intellectual building blocks and he has great aptitude for non-physical things, increasingly. Learning awareness of his body and the space he occupies actually enhances how he thinks.
This other parent probably felt a moment of doubt about how they've approached the reading thing and chose to criticise rather than sit back and evaluate the merits of difference in parental priorities