Reason says rent seeking is improductive and self destructive behaviour. One will engage in such activities only if the expected returns outweights the costs, which include the destruction of the system.

A rational person will not come to this conclusion under a system where such inefficiency is discouraged - pure and perfect competition, capitalism.

Many people wonder whether capitalism is a good thing. Bring them reason, science, let them work it out and make their own basic decision. Let them fight the bad reasoning themselves, come out of their local optimas if you prefer a math analogy. Racism and religious extremism must have some value, or such behaviours would not have because so widespread. But they seem to be local optimas, or even destructive in the end, just like rent-seeking.

Here is another way to look at this - look at the immigration net flows: it seems that more people want to immigrate in capitalist countries than emigrate out of them.

If it is reasonable to doubt my deductions, is it reasonable to doubt so many people may have made the same conclusions independently ?

Read about how immigrants affiliate politically, which belief system they adhere to. Apparently a lot of them want to be paid for the fruit of their labour, and not for pure idleness, want to be left alone - and many other libertarian values.

I'm sorry if that is not a valid explain for you. It is for me.