No, Cecil said and meant entomologists. Note the word “even” – it wouldn’t be surprising if the factoid were attributed to etymologists, but it IS surprising that it was attributed to insect-ologists.
You’re not alone in thinking that Cecil goofed (Cecil NEVER goofs), so I actually have the source: the entomologist was named Cole Gilbert. He was cited in Harper’s August 2000 (when the factoid was again published), but for a different nearby fact on the luminescence of fireflies. An article in the Oct. 2000 in the Vancouver Sun cites him as the source of the vocabulary figures. So it was a goof on the part of the Vancouver Sun, but an amusing one.