I think there is an argument that we are hard-wired to both detect cheats, and have an innate desire to punish them.
The
prisoner's dilema is a good example of this, as is the
ultimatim game. Dawkin's wrote about it extensively in The Selfish Gene. There are also good examples of these themes emerging in the current political climate.
So what you're feeling here is somewhat normal. As you say, it's just a case perhaps understanding the reasons underpinning this behavior, and dealing with it better.
