I completely agree with David. You’re more than welcome to join. The talk will be technical, but by being a regular on the forum you’ll probably have more of a context than most attendees. Also it’s an occasion to meet and have a chat around a beer after the event
If the field that asks for LinkedIn or GitHub can’t be skipped, I would create an empty LinkedIn profile and if there is a field with “additional comments”, I would explain there that I’m not on the platform but am into tech and follow the SAFE Network.