You couldn't even defend your position without using an example that you state is and always has been used for sharking.
Hiding fouls is indicative of poor character, and is cheating. Always has been.
I can think of many other examples. Take pattern racking as one. There was a time when pattern racking was considered a strategic part of the game. But many players and fans thought this took from the game, so many tournament directors instituted a rule saying "No pattern racking".
What's strange is the question remains "Is pattern racking allowed in tournaments that don't prohibit it?" This isn't so obvious. If the rules permit it you could say it is allowed. But the reason many TD's prohibited it is that many players felt it was a form of cheating. So if you pattern rack in an event that doesn't forbid it, some players will still look at that player as a cheater because they feel it shouldn't be permitted. Others would say if it's allowed in the rules it's not cheating. What this comes down to is the conflict between the rules and people's feelings about how they game ought to be played. I don't care about pattern racking either way, but while some would consider it cheating by today's standards, I don't believe it is inherantly a 'bad' thing.
Just because everybody did it and accepted it didn't make it right.
I sat on this statement most of the day. I'm out of my league here. I don't study philosophy or logic or debate. But this one puzzled me. I wasn't really sure. Other than "Everybody doing and accepting" something, what else determines right or wrong? It seems to me that for something to be 'wrong', there has to be someone to judge it as wrong. If it's not us as a society, who is it? I suppose from a religious standpoint you could point to divinity and God's rules, but I don't think he weighed in on not pointing out to your opponent you never got a rail on your kick shot.
I do think the idea that as a society we've agreed that dishonesty is bad. But what makes not calling a foul on yourself dishonest? I'll admit it is dishonest if the convention is 'we ought to call it'. But again, that's our convention. We are operating under a hypothetical society in which the opponent is expected to ref the shot and if they fail then they dogged it as much as if they missed a ball. In that world the player isn't being dishonest for not helping their opponent do their job, anymore than a player today is considered dishonest for not warning their opponent that they're about to shoot the wrong ball.
There are many grey areas in pool. Do you warn the player if they are about to shoot the wrong ball? What if they forget to mark their game on the wire? What's the difference? Is the first one a clear "No, that's their responsibility", but the second is "That would be cheating, they won that game". I guess it depends on who's responsibility it is. If it's the player's responsibility to move their coin then not saying anything is part of the game. If there is a convention that says we work together to keep the score correctly then it would be pretty snaky to not say anything. But this is all fluid depending on our conventions.
I also thought about poker. This is a game in which deception is built deeply into the game. Obviously it's not wrong to bluff or to disguise the strength of your hand. But the deception has limits. Some actions are taboo. They are called "Angle Shooting", and they are discouraged and borderline illegal moves to gain an advantage. For example, it's considered really bad technique to announce a hand you don't actually have. Suppose you got caught bluffing, instead of just mucking your cards you could excitedly announce "Flush!" If your opponent believes you and throws their cards away their hand is now dead. Even if you have 10 high you still win the pot. But this is considered horrible form. Some angle shoots are against the rules, but many are just against the social rules. People who do these things are shunned.
Poker is a great example of how some deceptive moves are part of the game, and others are not part of the game and hence not tolerated. My point is that if your opponent's duty to call foul on you is 'part of the game', then it isn't cheating not to do their job for them. If it's more like someone forgetting to move their coin, then I would agree it's not part of the game, we're all agreeing to work together to enforce fouls.
In the end I have no problem with the convention of calling fouls on ourselves. I do it and will continue to. I just think it's a more nuanced reasoning behind it all.
. Back then we didn’t care much for Mondays. 
