Executives get away with more crass offenses all the time but even if they didn’t, you’re ignoring a key power imbalance that defines this struggle. What purpose would it serve for an executive to post in this message board? They have plenty of recourse already if a bad hiring decision has been made.
I think we’re also conflating “personal” attacks with criticisms that just happen to be about one person in particular. The meme in the article is criticizing google for exposing their relationships to key actors in child imprisonment policies in the US (connection was exposed by hiring one of them). By this standard there’s no criticism you could make of the company unless it didn’t apply to anyone, which doesn’t sound very meaningful. The same criticism could be levied (with the same picture/meme text) if they decide to hire Mike Pence next year, will that also be considered an unacceptable personal attack?