If he's gonna ban travel to prevent Covid, then he needs to ban travel to prevent Covid. Unless there's something in the law that says he can't blanket ban, and citizens/VISA holders are entitled to entry. Is that a thing?
I generally agree - although if there are cautious procedures in place (such as specific flights loaded into buses directly into hotels for 2 weeks blanket quarantine), then the ban itself is only necessary up to the expected number of travellers and capacity for such procedures. This would, of course, take coordination and competence, plus genuine drive to stop the virus - all of which the US is lacking.
EDIT: Which terrorist groups were coming from Africa, at the time?
Short answer - none, really.
"The [2017] order imposes a 90-day travel ban on the citizens of seven predominately Muslim countries (Iraq, Syria, Iran, Sudan, Libya, Somalia and Yemen). It also indefinitely prohibits Syrian refugees from entering the U.S., and suspends the refugee program for citizens of all other countries for 120 days." - from which (since at least 2001, but possibly earlier) there have been only 28 convictions of terrorism (including 3 guilty pleas). Libya and Sudan specifically had had 0.
Chad was later added and then later dropped. Eritrea, Tanzania and Nigeria were all also added to the list in 2020 - which is what Biden was reacting to. Almost all the bans were just on not issuing visas which could lead to permanent residence.