Shorter Oxford English Dictionary dates the first recorded use to 1610, meaning "to blow or fuse together, to bring together; to compose; produce, bring about. Now rare." With a more modern meaning "to combine two readings into a composite reading" dated to 1885.

Maybe some people onthe Cat do misuse the word. However it's very easy to make up a sentence using "conflate" where confuse could be substituted and it would still make sense. Just not quite the same sense. I rather suspect that some of the posts Little Hawk is complaining about are examples of that.