Oooh boy, let me introduce you to the joy that is pediatric dentistry. I perform anesthesia at some peds dental places. Not unheard of to put full crowns or multiple extractions on kids under 3. I'm talking like at least one a day is that bad.
It does become an open wound in a real gross place for a while after pulling, I'd think any doctor of any sort would like to keep that to a minimum. You also don't want to leave them bare without a crown because they'll still have them for a while at least and cavities hurt.
I've been sat on a bus after work one time (maybe 10 years ago now) and I saw a mother open a 2L bottle of coke and fill up a bottle with a teet and pass it to a kid who was no older than 3.
That is simply not true, about breast feeding and cavities. Studies show that there are other factors at play, mainly linked to socioeconomic status, sugary/starchy diet and whether their water has fluoride in it or not.