Oh, it was an experiment all right--one they had no business attempting, but it was a different time. Now they do that sort of thing in SKorea... Heart surgeons did a lot of that in the late seventies and early eighties--this was surely a case of overreaching ego. I don't quite know what the evo-keeing is about, though. Would a chimp's organ have done better?
Yes, a chimp is a closer evolutionary relative so it stood a better chance of succeeding.
Others knew the risks and informed the patients.
This was an unnecessary risk taken by a willfully ignorant individual.
You can go on as much as you like about ego, but the doctor's clear statement was that the used a baboon because he didn't believe in evolution.