I think there are some very rational reasons for hating or at least strongly disapproving of the new owner.

For example, if the new owner of the company I worked for demanded on a Saturday that a new feature needs to be ready for testing by Monday, I'd be pretty upset.

Or, if I was on a team working on the problem of trust and ethics, and the new owner personally and un-ironically posted a completely false and inflammatory "news article" about a current event, and then several days later laid off my entire team, I wouldn't consider it irrational to be quite upset.

Irrational? It would seem to me that their fears were warranted.