I think that's mostly true, although there's also the case of the pathological sociopath that after making their pile of money, decides to whitewash their legacy through philanthropy, in order to appear to jump over to the other side of the U.
Armchair psychiatry is unwise. It's very possible for someone to be extremely ruthless in business while still being a genuinely empathetic and kind person in general. Not all sociopath-seeming executives are actual sociopaths.
People are what they are, in business or private, there is no such thing as 'another person'. Unless you're suffering from some form of multiple personality disorder.
Most people act differently in different contexts. (Do you tell your wife "Before I agree to take out the trash, I just want to make sure we're on the same page on what compensation for this will be?" Do you tell your investors "Shit, my investors are assholes. I'm getting reamed on this deal") It's not uncommon that different people will have different perspectives on whether someone is a nice guy or an asshole.
That's a questionable point, whether it is ethically right to be an "asshole" through your career and then donate it all once it ends.
I would say it (up to a point) is right. Donating/helping early in your life has a low impact, so the main reason I think it's reasonable to argue that way is that not everyone will donate at the end of their lives. So by gaining leverage early on (not contributing to philanthropy, not helping, etc) you will compensate for those who wouldn't donate and help make the world a better place once they got rich.
If you look a the billionaires out there quite a few will sit on their growing pile of cash until they die.
