Who ever wrote and handed out this letter to passengers has a serious problem with working in a service industry dealing with the public.
Sure there are lots of things wrong with working conditions both sides of the flight deck door. There certainly was when I was flying, and I would be surprised if much has got better now.
The first sentence "today I don’t want your attention on the emergency exits or on the oxygen masks, I would like to talk about something else and I would really appreciate your full attention this time."
Oh really, did the commander know this letter was being handed out. Did he/she know that passengers were being told to ignore a legal notice by way of the safety briefing? I could go on, but suffice to say that whoever the person is who instigated this letter can thank their lucky stars that this never happened on any flight under my command. If did, I would throw the book at them and ensure the authorities did the same.
If you have a problem with your job, go to management. If you hate the job anyway, seek a different career.