I’m not sure I would agree that this is lying or manipulation in the way that you would normally define those things.
I do think Elon is a bit of a troll, and also that he is prone to saying things that he thinks are probably true without really verifying them fully.
I think that he says things on social media with approximately the same level of internal surety that you might apply to talking to a friend in a casual situation.
You might be quite willing to say to a friend “we are going to finish the X project in 6 months” without really calculating the odds of that actually happening, and without your friend calling you a liar in 6 months when that doesn’t happen.
Now you can argue that he should apply a larger degree of rigor when positing on social media because he is a famous person running a big company, and maybe so.
But he might also argue that why should he be held to a higher standard on Twitter than any random joe posting garbage to thier feed for friends to read?