Talk about a tempest in a teapot! Tenerife is not even close to the same, neither crew knew that they weren't alone on the runway. Same goes for the accident at LAX when USAir hit the commuter plane sitting on the threshold.
The BA crew was apparently well aware of the circumstances and made an informed decision. Also, given the typical available "alternates" in that part of the world, Accra is generally a much better choice than a place like Monrovia for example, where they're not very friendly and not expecting you.