Why is there a registration fee for those who wants to register from Africa?
First, it's unfair to generalize the proxy ban for all African countries unless you are sure of this which is not possible since we have many countries in Africa and you can't possibly be in all of them to fairly try to open accounts. Even if you use a VPN, you can't be that jobless to start trying it for all African countries.
Personally, I don't see a fair use for the proxy ban when some new accounts could still be whitelisted, and people using VPNs to open new accounts. Good moderation would have done the job as in all forums, even with the stricter ones I've seen. This proxy ban approach would have made some skilled and genuine people abandon their accounts due to the evil tag. Paying for an offence they did not commit is gross and they might never think of coming back, while many of those who committed the evil become more experienced with the forum and use VPNs to open other accounts.
Talking about VPN, it reminds me of the stress I went through when I opened my account. It could have been easier for me if I had known about VPN registration then. It took me about a month in a bid to whitelist the account, and
all the suggested accounts to be mailed were mailed but none of them with "protonmail" responded to the mail. Not to talk of trying to query the person to know whether to accept or decline the request.
Thanks to @sfr.edits with a Gmail account, he was the only one who replied after a while and even apologised for the lateness. It was after some back-and-forth email exchanges between us that made him eventually whitelisted my account.