Seems someone doesn't want private access to the website, ie they want to track you, haha.
They intentionally prevented it.
AFAIK, even without Cloudflare, the web wallet will not load completely.
It's for their users' safety since browsing a non-onion / clearnet website via Tor requires it to pass through a Tor Exit Node that could perform a Man-in-the-Middle attack on them.
It could safely work if they have their official onion website though.