Complaining about the modern use of the word decimate is an odd and all too common pastime around here. I'm sure none of the complainers would bat an eyelash at the way the use of words like "logo", short for logotype, or "font" have changed and are now commonly accepted.
I myself have quibbled about certain words here -- I just got done with an extended conversation over whether "media" was a singular collective or a plural. Oddly, I took the traditionalist view on that one.
But "decimate" is long lost. It hasn't meant (exclusively) "reduce by a tenth" for centuries. I'm all for holding the linguistic line, but Carthago est delendo. Let it go.