IEEE charges significant membership fees and still most publications remain closed even to member. Typical rate for merely accessing paper is $33. If author wants to do open access then author gets charged $1500. How a person in poor African country supposed to pay these amounts per paper. A society with a mission of spreading and sharing scientific knowledge should not be doing this.
Can you define "significant membership fees"? I pay less than USD$300 a year for IEEE Computer Society membership in which ~$100 is for the full digital library (and similar for the ACM), so I don't consider that "significant". Sure, I'd rather not pay it, but it's not prohibitively expensive like the other journals are (where it can be thousands of dollars for a single subscription to a single journal).
$300 is significant membership fees for mere privilege of being called member of some society. I'm a member for few years now and have yet to experience any real value provided by IEEE memberships except to get spammed ruthlessly and get some discount to even more expensive conferences of theirs. Remember, even after paying $300 you don't get access to their closed publications (you just get privilege to pay "discounted" price of $13 per paper).
All these tells me this is enormously blotted organization mainly providing vanity and have no real mission. There are tons of non-profits that operate this way with their lavish expenses and highly-compensated officers.
If Elsevier was non-profit with nicely compensated "officers" then would you be ok about their ways?
Are you based in US or a European country? The whole point of projects like Sci-hub is to help people in poor countries where $300 is insane amount of money for getting access to a journal.