I didn’t knew that either, and there’s nothing embarrassing about it: pretty much every CLI tool that doesn’t have a clear name is an acronym (grep, cd, pwd, dd, yacc, etc).
Ping was originally named after sonar pings. Then later some guy came up with a weird acronym for a thing he did not invent. We don’t have to acknowledge it as a legitimate acronym. And as far as I can tell, the backronym is not a part of ping man pages, unlike with dig