The idea that capitalists should embrace altruism is a false pretense. The two are independent of one another, such that a capitalist can be charitable or exhibit altruistic tendencies, but it would be impossible to embrace self-sacrifice as that would mean disregarding capitalism entirely. Altruism is an emotional tendency, highly motivated by concepts that capitalists would consider irrational. Here are 3 examples where that is the case.
For the Benefit of Others
Capitalists should stop production and devote their wealth and lives to the public good. If this were the case, who would have jobs? A capitalist is productive precisely because he or she is able to create jobs, which help others create wealth for themselves, which fulfills self-preservation. Going above that is considered charitable or philanthropic for good reason. It takes a passion for humanity to invest in it.
Authorities Mandate Sacrifice
Force is not an adequate substitute for reason. The basis of our liberties are founded on the idea that excessive force is not a fundamental need in negotiation, that two parties can work out differences on equal ground without using coercion. In this difference of opinion, it would go against the founding principles of our society to utilize force or undue coercion.
Being labeled as greedy, and consequently being shamed for it, is akin to being bullied. Social pressure can be a powerful force, as is currently on demonstration in the United States government. Pressure alone cannot guarantee action, it is only a means to an end.
There are two sides to each of these arguments, and most people demanding altruism truly mean well. These concepts are not so black and white, and great effort is required to keep the wheels of society spinning.