I can't help but wonder: if 35 were identified as intelligence operatives, why did the US gov't wait until now to eject them? I can appreciate the need to perh

I can't help but wonder: if 35 were identified as intelligence operatives, why did the US gov't wait until now to eject them? I can appreciate the need to perhaps keep a few known entities around to feed bogus information, but allowing that many to just hang out seems like a recipe for trouble. Unless this happens routinely, in which case it likely has nothing to do with this "punishment".