That doesn't make much sense. Why would the easily-burnt trust still be intact at this point? It's a really weird comment if it wasn't supposed to mean "already burnt, or unable to burn".
I read it to mean 'already burnt or can't be burnt.' I'm aware of the definitions of 'inflammable,' but it just made the most sense in the context to interpret it that way.
I can't edit it anymore, but I did mean "unburnable". I realize (now) that "inflammable" comes from "inflame"/"enflame", but "in-"/"im-" has lots of use as a negation. "Invisible", "indivisible", "inconceivable", etc.