Well, I didn't see any reason to argue about this because to how people reacts over gambling they are taking it to the next steps without them knowing that gambling doesn't work that way, of course people could panicked and preached about gambling for fun but in reality it turns the opposite where their greed nature wouldn't allow them to continue just having the fun and stopping where the initial deposit landed them, you would see how someone wouldn't obey the rules of gambling instead when they lose they wouldn't mind just topping up to make sure everything they had already spend certainly comes back to them but without them knowing that whenever the system had you mind then that day could be their luckiest day but if doesn't then I think such person could be on a long losing streak, which as a result of poor bankroll management.
It depends, some people have the necessary and sufficient emotional control while others do not really have what it takes to control themselves so they end up with succumbing to the addiction that is being disguised with the delusion that they are only gambling for fun. Maybe bankroll management could play a part in all of this but seeing how sometimes some people are so passionate in gambling especially when they are losing their money, bankroll management would be the last thing on their mind.
I do agree that the advice "gamble for fun" is a slippery road, I mean that is how most if not all casinos in all shapes and form get you, they make sure that you have the fun that you are getting and that your mind is tricked into having the most fun of them all, ideally most businesses will do anything that is within the legal bounds to keep their customer so I do not blame them if they try to go for the psychological tricks behind the human mind to keep these rooms filled with gamblers that are having "fun" while in reality, it is just all mind games to make them spend more money.