Anecdotal, but a lot of times phrases similar to that are used because the real answer is "We don't have any way of knowing if users were actually impacted" and it's obviously far better for PR to phrase it that way.
It does sound better but here's the thing: this is Jeff Bezos. He's one of the most high-profile people on the planet. If his phone was hacked through WhatsApp, he clearly filed a complaint and told them what had happened. They just didn't manage to patch it for over a year and then stated they 'had no way of knowing' even though this clearly proves it happened.