The Grammar Commando has been quiet for a while, but it doesn't mean she's gone away. Just been distracted.
Also, the Grammar Commando is aware that words change meaning over time. This is understandable.
Sometimes, though, it gets taken too far.
For example, the word "decimated." This comes from the Roman practice of disciplining recalcitrant regiments by killing every tenth man. As a disciplinary measure, a pretty stiff one. It seems to have worked out for the Romans, though.
Using it to describe, say, an all but empty city in a post-apocalyptic setting makes no sense. If only a tenth of the population was killed, you could probably even keep the lights on and the gas stations working. And it's not like the root "decem" is all that obscure. I mean, if you made it through fifth grade you should have some acquaintance with decimals, and possibly even have gained some idea about the month of December.
So, if your disaster has wiped out roughly one in ten people, then it decimated the population. If it wiped out practically everyone, use a different word. Obliterated might work.