That does seem offensive and without seeing what advice has been given to pilots affected by this it seems insensitive and no doubt very disconcerting to those involved.
I acknowledge the fact that this letter is susupposedly designed to advise AOC holders of a change that may affect pilots that they employ but to couple it with the statement that Sunfish has quoted above is in my opinion threatening and insensitive.
My thoughts are with those that may be affected by the upcoming review.