And that's not even starting about it being a European initiative for European citizens and hcaptcha being a U.S. service.
(source: work on hCaptcha)
and if you pick for them not to email you, they try to trick you with dark pattern (all trust gone)
This website looks untested with Firefox and an ad-blocker, which really is not uncommon for people worried about privacy.
It's already bad that it want's your complete name and address. Yet another data set with me in it that will get hacked and sold at some point. And, without knowing what else it's going to demand on the second page. What if it suddenly asks for stuff I don't want to give on page 2 (copy of passport or something)? Now I have already given my name and address, and that is already in that database, so if I quit at that point I've just put my personal info in a database for nothing.
I get why they make it so hard to participate as a citizen though, the EU isn't exactly democratic.
It's a pity, I support the initiative, but I fear they might get far fewer signatures as people who are willing to sign. Maybe their captcha service has decided not to support the initiative?