It seems public access has been removed.
It isn’t really a problem, the Activation Zone is very big and a large part of it is the public access road that goes over the hill. There are plenty of places to do an activation - even on HF.
I don’t think there ever was official public access to that summit point, but on some of my visits, the gate has been open and plenty of people made that short detour to the summit.
However as Colin says, there’s plenty of spaces beside PROWs well within the AZ.
A ‘private’ sign has been up for a few years. I have previously used the gate post to fasten my pole to.
I recall that a contest group was operating near the trig point at the time. I guess they had driven up as several cars and a large antenna were visible from my operating position in the distance.