Perhaps it should have been kept quiet as I am certain the internal memo/email was as it states an internal memo/email, a company such as Monarch would only want that sort of information in the domain of the public if they the company made an official press release.
I will give you an example
I work for one of the major cruise lines and a few years ago a surprise announcement was to be made to the public concerning the deployment of a particular vessel to the UK cruise market, I at that time I was on a similar site to this but for the cruise industry and one of my team had posted the information online. It didn't take long to find the culprit as he was openly discussing it online and with others, regardless of the fact there was going to be forthcoming press release the person involved was instantly reprimanded and subsequently demoted due to gross misconduct.
That's why I find this whole saga involving members of staff discussing particular internal memos or emails of there company to the public as posting them on PPRUNE. This may be a rumour site but it doesn't give a green light to those wanting to discuss what should be pvt internal emails.