Same reason why honest signals exist. A peacock with very rich feathers is a fitness disadvantage. But they find mates more successfully. These traits persist in the gene pool.
It’s so much easier to just evolve a cheating trait that does the job of finding a mate even without the required fitness.
But the signals stay honest for the most part.
Why?
It’s because ultimately the species survives, not the individuals.
In a lot of cases, something that makes the individual more fit also makes the species more fit. But in some cases, they are inversely proportional.
Hence you end up with suicidal genes that favor the death of the individuals for the greater good of the species.
Now extrapolating to human society, most nations have landed on a system where taxes are paid to the government. Every individual might complain and try to get out of paying. But we do. Why? Maybe because societies where that wasn’t a thing were less fit and didn’t last long enough to still be around.