I've seen far worse signs in much better zoos. The fact that there is an informative sign to begin with is a good start. It's obviously old, ugly and now outdated, but giving a scientific name, taxonomic background, habitat and often diet, puts it a fair way above many modern zoo signs.
You also seem to be forgetting, too, that the sign needn't have much English at all. In an Egyptian zoo which sees only a very small number of tourists, the Arabic is what matters, and as far as I can tell, that's fine. There are far more prominent official examples of worse use of the English language in Egypt.