The first half suggests that he might go through with the transaction of taking Tesla private, meaning, acquiring sufficient stock for cash that it falls below the SEC reporting thresholds and delisting it from stock exchanges.
The second half of the statement states that, whatever he decides, he has already lined up the funding necessary to carry out contemplated action in the first statement.
People don't interpret the "funding secured" to mean that he has a going-private deal locked up. They do interpret it to mean that he has locked up whatever financing he would need to go private, were he to choose to do so. And the problem is that his follow-up blog post, tweets, and Tesla statements indicate that neither the going-private transaction, or the funding for such a transaction, has been finalized--or even has progressed to the point of concrete terms being discussed.
If it was, then nothing happens (except a strongly worded letter from the SEC on proper disclosure methods). If it wasn't, however, then at the very least he's going to have to pay restitution to all the investors (both long and short) who lost money as a result of the tweet. At worst he's going to prison.