He's not talking about a framework, he's talking about web application firewalls that only support the default verbs. It's quite common and has nothing to do with which framework you use.
Thanks for clearing that up, yes, as I've said, you should not use custom verbs if you have to interop with firewalls or proxy caches that perform DPI unless you've tested them.
Problem is that you may test the system now and it all works fine. But the day after you deploy, somebody named Murphy adds or updates a proxy somewhere in your topology that breaks things. Or your organization gets a new customer or partner with a differently configured network.