Well...why not 'social interactions'? As far as game mechanics are concerned, aid and plunder function identically, as I pointed out in an earlier post. We don't really think of them as the same type of action, but they are, so using one term to describe both of them does make sense. Even if (again) everything you do to another player could be considered a social interaction, all of those already get filed away under another header as well (taverns, trades, etc).
Anyway, while an odd thing to 'update' it's always been the case that aid and plunder have both appeared under what used to be the 'aid events' filter, so changing the name of that header to something that doesn't make plunder look odd in the list kinda fits in my book.