I don't really accept moral arguments that argue that one thing is a better use of one's free time than some other thing. Even the best cancer researchers have every right to use their free time to watch a movie or read fiction instead of working on solving problems, even though they could theoretically save human lives by doing so. If they get to, then surely people who write programmer tools to search files get to do whatever they want in their free time too.

The author chose to spend his time writing his own file searching tool instead of trying to work with GNU. That's his call.