In universe, that works. The sad reality is that the goatee-and-shaved-head look (which Avery Brooks sported both in his previous TV roles and in real life) was considered by studio heads at the time to be "too urban" (ie, "too black"). It wasn't until the show had established its roots that Brooks had enough leverage to change Sisko's look to what it should have been from the start.

They touch on this in What We Left Behind.