Except the idea of capitalism is, that society can benefit more from allowing people to invest their excess money into growing industry rather then having them put the money under a pillow or immediately spend them on unnecessary luxuries. More industry usually means some return on investment for the investors but also more taxes being paid (taxes being a percentage meaning they scale with industry size). So capital investment is supposed to be win-win for investors and society. Just the current (mainly US) system is so corrupt and mismanaged this does not reflect into practice due to tax loopholes and consolidation. So punishing the investors instead of fixing the system is hardly uncontroversial and informed take.

Also, with the specific batman example, if you really want to help people, doing charity and publicly beneficial work yourself will almost always be more effective than giving the money to a government to use. A government has to have strict anti corruption measures that are publicly auditable to minimise corruption (or loose a lot of money to said corruption), but these make government very inefficient. Just look at the USPS truck procurement for perfect example. You don't have this issue when you have one owner of the money who can make unquestionable decisions (because it is his money). That is not to say we should rely on billionaire charity, absolutely not. But it just shows how underdeveloped the take in the post is.