I agree with PilotLZ (as usual). Even though his example was not 100% proper, the idea is axactly the same. The shop owner does not advertise cigarettes in this case, only because there is a law stopping him from doing so (obviously because it is damaging to the health, not just the pocket - as the case is with training). How about car manufacturers then? They are still selling and promoting diesels and petrol burners, even though we ALL know that their days are numbered (AND they are harmful to the environment and to our health). If one still wants to buy any of them - for their own reasons, by all means they can go ahead and do so. There is nothing stopping them, even though for most of the others it would be a stupid idea.
This is capitalism, this is business. The dealer, the flying school, the real estate agent, the whoever salesman, will always try to sell to stay alive in the business. It's up to the "buyer" to assess and decide, and there's nothing that one can do other than offer some kind advise, and yet is only according to his/her judgement.