I don't have google services on my phone and having every app permanently connected checking for new messages is detrimental to battery life. UnifiedPush is the open alternative to Google Cloud Messaging: https://unifiedpush.org
I'm talking about the user voice site in this post. That doesn't use sign in with SimpleLogin or sign in with Proton (which also exists). You can sign into SimpleLogin with Proton.
Ok now I get what you mean - I fully agree. UserVoice really sucks as a platform, but there aren't many good alternatives and I imagine they don't let you migrate and move the existing feature requests, so Proton is stuck with them.