Don't spread misinformation. Back it up with fact or don't post it at all.
2 things.
Either
1: Nobody has any hard fact on this yet, so it is all speculation, ergo, misinformation by your logic.
or
2: He wasn't spreading misinformation at all, to do that would be to pass off baseless opinions as hard fact. He wasn't doing that, he was supplying a likely scenario based on the information at hand, a hypothesis. Since when did hypothesis = someone making stuff up then passing it off as fact?
Take your pick, either way, you're wrong to call him on it.