Unless I misunderstand the purpose of Forge/FML, this statement is a bit ludicrous as FML is an API for other mods. So an API that is not being called may appear very stable and only after an application utilizes it would an error be uncovered.
Looking at the trace, I do not see anything from Eurys but do see a number of possible points where FML may be involved. Even if Eurys passed a bad struct in that is the ultimate cause of the error, I would think good programming practices would require Forge to fail gracefully and return a fail to Eurys, not crash.
So as I look at it either every failure is a mod's fault that connects to Forge, since Forge when doing NOTHING does not crash, or Forge needs to take some ownership for failures that occur in Forge's codebase. After all the NPE happened in an FML class...
Of course I am not a Java developer, having hung up coding to move into management when C++ was the standard dev language...