That's likely because they are tired of dealing with conservative PCPs and or paying 200 bucks a month to a clinic that will start them on 200mg per week.
Honestly, I think most family docs are going to balk at much more than 100 to 125 a week. You know some of the dumbasses / trolls we deal with here? Imagine your license, not to mention patient health, being in jeopardy dealing with people like that on a daily basis.