Hey, thanks. I'm no need of this but I figured out that I may not be the only one sticking more than one proxy on a GO and thought it might be a good thing to have a straight way to realize a complete purge.
It seemed tricky though because of the way Unity and Playmaker combine since Unity is built with the idea of using only one instance of a given component, at least a native one, and it shows when referencing FSMs from within a FSM. I wasn't even sure that an action would be able to properly parse all FSMs on a GO without knowing their names, where in fact one would need a way to access Unity's own "secret" way of listing components.
But then I still looked into the actions that target a specific proxy and saw that they, in fact, already rely on an array by getting all components of <type> but specifically avoid all proxies that don't have a name matching the reference. :-)
So maybe the Destroy ... actions could have a special mode where if the reference is empty ("leave empty to remove all <type> proxies" kind of stuff), it will simply destroy all proxies of that type.