That was absolutely poor examples. What policies actually worked to lower the black unemployment. Remember, black unemployment was dropping, due to Obama, before Chump put his policies in place.
About the border, first of all it is kind of insulting to conflate illegal immigrants with affecting black employment. Secondly, these immigrants do the work that most Americans of any ethnic group don't want to do. Closing the border, in which you can argue if it was even done, had no immediate impact on black unemployment. On a side note, enforce the laws restricting hiring illegal immigrants in the first place. Then they won't want to come.
As far opportunity zones. They offer no immediate impact to lower the unemployment. I live near Gary, IN. Gary is just as jacked up now as it was before Chump to office. Ain't no opportunity zones set up in Gary. Sure they sound good but these things takes a long time to develop. Years in most cases.
As far as HBCU's, just like the black farmers why are they treated differently than white counterparts. Anyhow, the HBCU funding was started by a black congresswoman, Alma Adams. It was passed, bi-partisan in both houses and sent to Chump to sign the bill which was veto proof. Naturally, Chump takes credit for it as if it was his creation.
Therefore, these policies were weak at best. Jim Crow died in the 60's. Today's racist with help of Lee Atwater have found ways to be racist more subtly.