And by 'seizure', I think it is pretty clear that I mean 'revoking access to', in the same way as in the OP Google has revoked access to the given Google account.
Edit: Godaddy is not just a (crappy) registrar. GoDaddy is also a (crappy) hosting provided which I moved an organization out of.
Edit again: I guess I ought to explain domain names to you. Most DNS providers are crappy (unlike Cloudflare), and have a non-negligible TTL. Even if AR15 had access to GoDaddy's account to change their DNS records (A record for the www subdomain and root domain), it takes a while for new records to propagate globally.
More likely, what happened is GoDaddy told AR15 to take their domain to someone else. And thats what they did.