> Are you also of the opinion that you can't buy used phones?
Depends, if you want a throwaway phone for a call or two that are not important, go ahead.
But if you're looking for a phone you'll keep for multiple years and you want the least possible risk of being tracked by someone else than who made your phone, then I would absolutely not buy a used phone.
Small problem as OK phones can be bought for ~$100 or less in most parts of the world.