Three things.
First, I don’t see that the fact that Namibia doesn’t have an illegal immigration’s issue, as do Canada and the US, is relevant here. There are lots of reasons countries may impose visa requirements and illegal immigration is only one. In this case, as Namibia is saying, it’s a question of fairness.
Second, the amount is really nothing in the grand scheme of things. About the cost of a box of shells. Less than a day’s tip for a PH. And we charge them, so they charge us. On a tend day hunt, it’s less than $9/day. Again, fair is fair. Oh, and they could use the money way more than we in North America.
Third, Namibia, and Africa in general, are still the greatest places in the world to hunt - the variety of game (including especially dangerous game), the hunting biomes, the cultures one encounters, the number of animals one can take on any given hunt, the value equation, and more, mean that Africa will continue to be the world’s greatest destination for hunters for so long as hunting is allowed.
And for what it’s worth, Africa governments may be (actually generally are) corrupt, but at least the corruption is relatively visible and minor for the average hunter (it’s different for those who live there, I admit). The corruption which exists in North America tends to be generally more hidden. We aren’t any better. We’ve just made a science of it. That’s not to say I’d rather live there than here, but we need to be careful about patting ourselves on the back too often or too hard. Could break an arm.