Yes, it's a JS-heavy website with a webdesign that makes my eyes hurt. Sigh, can't have nice things, can we?
You can skip right to the signing by going to the relevant Citizens' Initiatives website on europa.eu here:
https://eci.ec.europa.eu/038/public/
Both sites seem to work fine in a Tor Browser, and the signing requires solving a self-hosted captcha (no Big Tech captcha involved, it seems), so at least that's good.
The main method is to look for a verified website link, and in some cases the server addresss of the account will also verify identity.
For example, if you look at @thunderbird you can see it's the official account because it has a verified link to Thunderbird's official website.
Another example, the European Commission's official account @EU_Commission is genuine because its account address shows its server is at europa.eu, which is the official European Union website.
This kind of address system has been around since the beginning of the internet, so the problems and solutions are well understood.
It's important to pay attention to the server part of the address because this tells you where the account actually is.
For example, the European Union has lots of official accounts on here and we know they are official because they have "europa.eu" as their server. Only the EU has control of that site.
Email has the same issues and solutions.
GNU social JP is a social network, courtesy of GNU social JP管理人. It runs on GNU social, version 2.0.2-dev, available under the GNU Affero General Public License.
All GNU social JP content and data are available under the Creative Commons Attribution 3.0 license.