I agree that pediatric practices refusing service to no-vaxers is the norm in the US.
I've have a few friends who range between full on anti-vax vs being skeptical of one or two, and I’ve heard a few stories.
It seems that a parent asking for their child to not receive one or two of the 20-50 vaccines the pediatrician gives by default has about a 50% chance of being kicked out of the practice. As you said, asking for no vaccines is about a 99% chance.
However, pediatricians have a racket where they will not accept a new child (unless they moved to the area) unless they saw the child within a week of its birth. Thus, when you get kicked out, you are out. You can't see a pediatrician anymore unless you drive 80 miles to sketchy 90's new-age pediatrician in a dingy strip mall, and you can't get any more vaccines unless you go on the correct afternoon of the second week of the month to a government clinic in the part of town with litter and shootings.
This has pushed several people I know into not getting further vaccinations when they were getting 95%.
Maybe it's just our area, and the whole US isn't doesn’t have pediatric practices like this...