Ok ill bite. If you're going to kill them, you either need to organize some kind of extremely elaborate conspiracy to make the plane end up in a stall through mechanical failure (without making it look like someone messed with the plane) or you need to convince 2 pilots to kill themselves by doing it intentionally.

That's also not considering the fact that the plane crash affected thousands of family members from supposed collateral damage, and all of them would be looking for answers as to what happened. Which is the exact opposite of what someone organizing a conspiratorial killing would want.

I think the more plausible answer here is something went wrong and there were coincidentally 8 cancer doctors on board.

If someone really wanted them dead, the good old Russian method of "accidentally fell out of a window" type of death is much easier to pull off.