Every time I hear "you can't/shouldn't use a .22 caliber/.223 for whitetail deer hunting", I just roll my eyes.
As I kid, I used a .222 with 63 gr. spire points for deer hunting.
Then I used a .243 with 75 gr HP for a few years.
Then I used a .223 AR with 52 gr HP for probably 25 years.
Currently, I use a .224 Valkyrie AR with 69 gr HP.
I won't say I never lost a deer or had one run that I had to trail with any of those guns. But I will say in most cases the deer was DRT. I hunt northern MO. While they aren't the largest whitetails in the country, they are not the size of dogs either. I body shoot most of my deer. Up until the last several years, we would do a lot of deer pushing, so my shots were on running deer, so it is just easier to hit them in a vital part of the body, instead of the neck.
As anyone with any intelligence about hunting/firearms knows, it is about bullet selection and shot placement.
Yeah, you can go for the bigger calibers and heavier bullets that will kill by the shock of the bullet hitting the deer, pretty much no matter where you hit them. But if you were a better shot, you wouldn't have to. And unfortunately a lot of hunters shoot one time a year...during deer season...and they are marginal shots at that. So I can see why some places have minimum caliber restrictions.