Do you know the source of this?
http://www.acandyrose.com/patsychart-rn2full2.gif
Seems very damning for Patsy if real.
You may be right, but I really find it hard to tell from web resources that scatter from supporting one side to the other.
See, for instance, JonBenet Ramsey Case Encyclopedia.
One of the things that struck me from the very beginning, was the way the letter "a" was written. Notice how they are completely different on the two samples from the photo.
Whoever wrote the note, uses a very uncharacteristic way of writing the letter "a".