I have read up on "decimate" and etymological fallacy. I guess I would have said that hearing decimate used as a substitute for destroy did rub me the wrong way, and I did think it came from the Roman kill every tenth man thing. But to me decimate still means reduce or damage significantly, not to completely destroy. If it simply meant the latter, it would be just another word for something we already have words for without even any additional nuance, which seems annoying to me. I have no idea whether my formulation of this is supported by scholars.
I mean, you guys got it all wrong. A decimate is someone's tenth wife.