I think they both chose a terrible name.
Larry Wall used grep over a Usenet feed to be sure that he would catch all references to Perl. (He did this before Kibo popularized the technique.) He therefore wanted a name that (among other things) would have very few false positives.
Also, some forums don't allow you to search for single-letter names.
On the other hand google was unlucky. They lost on public relations on this issue.