You maybe right for now, but in the future it might change.
When African crypto enthusiasts have better knowledge, experience, and of course better skills, both technical and scam skills (LOL), your statement might not be right anymore.
Fortunately, time will help investors become more knowledgeable, and with their own experience, precious lessons in crypto for years (losses, invest in scam projects, for example), they might become smarter and more carefully with their investment.
Consequently, over time, scam projects will harder to get succeed.
Anyway, in other side, scammers always find out ways to adapt and make more complicated scam projects.
It would surprise you if you carryout some research, the most professional scammers are Asians they were in charge of all the ico scam am not sure we have Africans with enough blockchain experience to run a successful scam.