The word 'decimated' is now being used in place of 'devastated' or 'crushed'. The etymology of the word points to the 1-in-10 killings in mutinous Roman legions and to 10% taxes.
This blog entry makes a strong case for just getting on with things and use whatever meaning is in vogue at this time.
So, what keeps me from using this word in the manner in which Donald Trump uses it, or even some erudite scholars have started using it? Well, it is the 'deci'. It is hard for a person schooled in science to ignore the 'deci' or 'decim' prefix that implies 'tenth'.
Unless there is some approximation of 'tenth' implied in the situation I still can't see myself using this word, despite modern usage.