Hm, I guess I wasn't specific enough - you're right that you could just be excited by the mission of the company and that seems healthy and cool. It's the borderline worship and the cheering (to be fair I think this might be an American cultural thing) that seems off.

Or maybe it's my gut feeling that many of the people involved in aforementioned rah-rah-rah behavior are just putting on their "work persona" face a little bit too enthusiastically, which itself feels a bit sus to me.