That being said .. it's still just a virtual check. If you write a real check to someone and they cash it and then don't give you what you ask for, you do have to get that person or entity arrested or take them to court somehow.
Even if Zelle was an official US federal reserve system (which it really should be and not this hacked together bank program), I think you'd still have the same exact issue.
Judging from the comments even Venmo appears to have the same issues, even though it's owned by PayPal. Their parent company PayPal has some protection because there's that buffer that exists in the PayPal account before it goes to your bank account (although I though Venmo had this too?) so they can recover money from that layer, but not always when it gets transferred all the way out.