many people who experience losses and other negative impacts are usually because they lose control and this loss of control begins with those who are emotional because they get results that are not in accordance with their expectations. besides that people like this usually put high hopes on a bet they make by thinking they can get a big win and make them go home with a bag full of money, but when emotions are out of control they will most likely only regret the behavior they previously did because it will make them continue to bet again and again.
You are right, we must be able to see ourselves, whether we are ready to lose what we bet or not because those who experience emotions are usually the type of people who are not ready to lose with their bets that are made until the defeat that occurs triggers their emotions and makes them lose control of themselves.
And with that they mostly added more money and repeat that same outcomes, betting against the public most of the time are being use by those experienced gamblers, they understand and they know how to work with emotions, if they lose then they let it go, as they know that there are many other opportunities if they will analyze and assess each underdogs that they will entrust their fate.
Self-control helps to manage your bankroll, with good grasp of it even how often you bet against the public you'll be able to lessen the amount of your loses as you know your limits and you know the risk that you take.
I think regardless of whether you bet against the public or with other options the most important thing is one thing that understand the dangers that always lurk you at all times, because in any case defeat will always be part of the game, but I also agree with you that most likely the gamblers who are able to control themselves and their emotions are those who are already experienced enough because of course they have gone through various situations and maybe make it a lesson so they can be better as a gambler.
The point is if you want to be safe and avoid the bad possibilities in gambling such as experiencing large amounts of money loss then understand what and how gambling really is, because in most cases the gamblers who experience a slump are those who gamble blindly without being based on any risk management, so realize that defeat will always be part of the game regardless of how you play.