OK let me qualify my answer. Voluntary financial arrangements are beneficial to society that do not harm others. The government in capitalistic systems enforces the rule that you can't harm one another arbitrarily. So an assassination contract would be illegal. Also, defrauding people with cold calls of their money is illegal. In short, LEGAL voluntary arrangements in a free market are beneficial.

And this is just one (extreme) instance of “person A pays person B to destroy person C's value, for net harm”. Imo, the only failing of capitalism is that one can profit by destroying other people's wealth (though this is probably splitting hairs, given how varied the ills that come from that).

Everybody has their price. For some people, it's low enough that they'll actually do the evil things and not lose sleep over it.