When did they close the pier? The National Park Service website has an accurate, regularly updated list of the closures. Their NPS alerts listed the West Bluff parking area (Warming Hut) as closed, but the pier (Torpedo Wharf), wasn't specifically mentioned.
Given the incertitude of the various announcements it's really hard to say what is or isn't allowed in some places. I ceretainly can't answer your question but Glen may be able since he's much more knowledgable on the the closure regulations.
Is anybody could explain what is a DIFFERENCE between Golden Gate park, where (thanks God!) people could walk and even make party and Crissy field or Ocean beach where access is banned? Is fresh air on the Crissy field more dangerous vs. Golden gate park? Looks like it is bureaucracy idiotism.
If you can access the Presidio's Crissy Field webcam, use the zoom feature and point the camera at the pier. You'll clearly see that there are usually a good number of people on the pier. As Happy Wanderer said, the problem is finding parking that's a REASONABLE distance from the pier. You'll have to decide what "reasonable" means for you. But as things stand, you're looking at a walk of about 3/4 of a mile if you can find a space. And there's a two hour parking limit for cars that don't have the neighborhood's residential parking sticker.