"For all intensive purposes..."
I had a co-worker and he admitted that he'd been hearing, saying, and writing it all wrong for well over 20 years.
"Decimate" to mean something other than relating to the old Roman military punishment of removing every tenth soldier in a line.
Mike
So, Michael...words can only keep the same solitary meaning, spelling, and pronunciation for centuries before and the eons to come?
Words and phrases certainly evolve, but I like it better when the evolution is done on purpose by people who knew what the existing phrase was and deliberately chose to extend or modify it, rather than someone who misheard it or didn't understand it in the first place.
That's generally how languages evolve. A word's meaning extends (obviously not literally poking out), and if left (not as opposed to right, and not meaning weak/feeble) to specific and limited instances, would remain (as opposed to parts left over after staying in place) moribund (ew, yucky)...so I would have to describe something as clumsily what I just typed out (uh, but not on a typewriter or letter press).

It's true that words or phrases can suddenly receive a more extreme meaning or a reduced impact but while one scribe might have used the right words for the moment, another can pick them up and reuse and reassemble them for their interpretation of witnessed events. Or for extreme attention-seeking didactic purposes and memetic distribution.
In the case of "decimate", it wasn't going to get reused again for obvious reasons. Perhaps a better usage is "to quickly reduce by 10 percent and the resulting effect(s) thereof..."