In my opinion she should give some of that to the Amazon employees on the backs of which the vast fortune was made. Jeff and Mackenzie really fucked over the vast majority of people that work(ed) there usually through lies about RSU's, firing people before 90 days who were expecting health insurance, timing their pee breaks, etc.
Even if I agree that she has made a fortune on the backs of Amazon employees, I don't agree with this comment.
Here, MacKenzie Scott has made a choice to give money back to causes which support underprivileged people (which will doubtless include some of those same Amazon employees), which she did not have to.
You seem confused. The ideas that you say above, that workers should get health insurance and shouldn't be timed on their toilet breaks (workers shouldn't be exploited) are quite literally "leftist" ideals.