They know. They're saying to read the original tweet more closely. It was very carefully phrased. Technically, it doesn't say what everyone assumes it said. He

They know. They're saying to read the original tweet more closely. It was very carefully phrased. Technically, it doesn't say what everyone assumes it said. He never says "Sam has accepted an offer of employment." He just says he's "excited to have [Sam] join" and he's "looking forward to" working with him. All technically unfalsafiable statements about his feelings and state of mind. They're even addressed -to Sam-. They're the kind of thing you could imagine someone saying to you at the end of a job interview that ended with an offer which you technically haven't accepted yet.