Maybe that question is to clear out his doubts to use dome strategies he read up used by other people and same as you said there's nothing wrong to use it or any other else as long as there's no exploiting or other abusive things they do on the casino. To many people use that and experimenting other strategy to use and they are fine so they should try it since somehow those strategy mentioned is really fun to use.
You can use whatever strategy you like because it's dependent on your mindset but martingale is not too much fun if you have limited bankroll because of it's aggressive betting behavior in order to win but still we all have different opinions in gambling and for some it may work while for others it's the same.
There are very few stories that i come across about their success in martingale using
though there are many who had said to experiment this strategy but ending not satisfies with the result.
so i think that indeed that it is depend in their opinions and belief but at least we are sharing what we do understand from our experiences and from what we have watched and read over the years.