Then why do they have a lock on their phone? Their house? Why do they wear pants? They already won’t give their phone number or email address to anyone who asks. They already practice privacy.
It’s not about having something to hide, it’s about protecting what you share against misuse. Think identity theft.
Contact your MEP. Online petitions do nothing
https://archive.is/rYiwP
Doesn’t seem all that significant to me. If you don’t want then to have your event info, don’t give it to them.