I think the fact that you and I, and everybody in America, knows who the Westboro Baptist Church is is interesting, considering they’re a group claiming 70 members in Topeka, Kansas, and they never actually end up protesting anywhere that they claim they will, yet seem to get a lot of media coverage any time they suggest they are going to protest at places like Leonard Nimoy’s funeral. Prior to this incident, and even still despite it, the vast majority of people you could go out and talk to have no idea who or what the Black Israelites are. I’m familiar with them because I’ve actually come across them in real life, and they are actually more prominent out among people — not on the Internet or in media, but actually out on the streets, but yet everyone knows who the WBC is.The answer to this is fairly obvious, it's the same reason you don't see a similar call to do the same to groups like the Westboro Baptists, they're known wackos, who are apparently quite proud of their behavior just like these black israelite street preachers.
Now, don’t get me wrong, because I don’t think Black Israelis need more coverage because they are a huge outlier, as is the Westboro Baptist Church. They’re both irrelevant, but both could be used to stoke the flames of irrational fears and to drive bias, and one is certainly much more prominent and well known than the other, despite being significantly much fewer in number (and only one congregation).