A good eq can indeed hide many flaws...but it's also fixing things too, it all depends upon how you look at it. If the 6kHz signal needs a -4db attenuation because of a hot response at that frequency, it is indeed fixing the response...or hiding the peak. It certainly doesn't fix the speakers natural response, but it does fix the overall sound. Imagine the world without equalization! It's used in virtually every aspect of virtually every thing recorded or played back.
Lets say you have a nasty turntable rumble well below your subwoofers capabilities around 20Hz. This signal while likely inaudible (unless using very expensive subwoofers with superb extension) is potentially very damaging to the drivers...audible or not. A nice shelving of the 20Hz filter and presto...problem fixed!
This can be interpreted in different ways...is the glass half full or half empty? Both are good points and both are quite valid, though personally I believe the "fix" term carries more universal validity.
It's all good really...and tends to make you think a little now doesn't it?!
Bob