Move on..... it is a total waste of your time trying to figure out why someone does anything in this world of ours.
I, too, do not see anything wrong with the content of your Introduction PM. The only thing might be that you did not give enough time between your first contact and the time you want to meet. Look at it as time-management, if she has X people that fit into her schedule with screening already handled; then screening someone new with little or no time is not worth her time.
We have all been there at one time or another.
Just saying......
Move on.....