I'm interested in the ramifications of the timing here.
The boundary-setting letter ("these grifters don't represent me or any of the RF, so don't be fooled into unrolling the red carpet") is coming after Harry has committed to moving back to the UK and educating his kids here. With the odd visit from Meghan, of course, when she can spare time from her busy busy life of fruit spread.
This is really terrible timing, from the HAM point of view. Too early for them to have got their feet under a lot of tables, and too late for them to change their minds about moving here, unless they want to lose an awful lot of face.
And the timing is entirely their own doing. They hid their plans for as long as possible, and then announced them to KC at the last moment, as a fait accompli. (I'm still awed at just how unnecessarily rude it was, actually, to meet with your dad and deliberately not mention that you were planning to move back to his country in a few weeks. Just utterly abnormal.) So there was no previous opportunity for the RF to clarify what their position would be.
HAM played a stupid game and won a stupid prize.