It's possible he thinks Tesla is radically undervalued because of the role of shorts, and that while the stock could rise in coming quarters it also could be very volatile and could also become undervalued again during any difficult times ahead (ie., Model Y ramp, AP crashes, missed quarterly guidance, funding raise, etc).Per ER, Tesla is entering a phase of perpetual profitability and cashflow positiveness. Shorts would be continually grinded as stock will continue to tear up... So why exactly is Musk concerned about shorts?
Also, Elon could also be concerned that the media attacks against Tesla and their products is starting to seriously impact consumer's opinion of Tesla in a negative way, and this significantly hurts Tesla's mission. He could also be realizing that the shorts' involvement could continue even after profitability in a way stronger than most expect.