In that case most capitalists and owners don't understand capitalism, because there are only two standard arguments - one is the one about risk, and the other is that everyone should be grateful when a capitalist creates jobs at all.

As for defences - capital is just political power by other means. If the capitalist is wasting money on yachts while workers can't afford food and housing, the return is morally disproportionate, and the usual outcome is socially catastrophic, in various possible ways.

Capitalism reduces every transaction to personal opportunism, with no concept of broader consequences. That's a shockingly stupid way to run anything - as we're all about to find out.