Kettlebells aren't a controlled substance. You can do whatever you want with them. You can walk into a store and buy one without anyone questioning you. Why should you then have to turn around and pay somebody to teach you how to use it? Should you need a fucking license to operate a kettlebell? Then you're supposed to pay somebody again to teach you how to teach someone else. Fuck that. It's a fun toy; fucking play with it.
Same goes for any other type of exercise. Working out is free.
You can work out with a horse if you want to. You don't need anybody's permission.