My argument is that even small organized crime groups were capabale of sophisticated operations so it's absolutely not far-fetched to assume that they may be able to implement end-to-end encryption apps. Whether this "organized crime" is "wrong" does not make much difference. It might be even easier to find people to implement it as not many would have moral issues.

Speaking of moral issues, cheating on casino is pretty much off limits on my personal moral compass. That the attack was possible within the normal mode of operation does not make it less of a fraud. Imagine if the casino would reverse-engineer a slot machine and find a way to abuse it within the normal mode of operation, making odds (even more) in their favor. That would be fraud, plain and simple, and I don't see why a player should be held to a different standard.

You are absolutely right, not everything unlawful is wrong. But I fail to see which benefit we as a society would have by allowing exploitation of technical deficiencies in slot machines for profit. It is a crime and it is wrong in my book.