If Elon believes he can immediately put fresh cash to work productively to speed more rapidly toward Tesla's goals, sure, present a subsequent offering of shares while the price is near a record high. It could push all competition many more laps behind.
We really shouldn't be overly desirous to hurt short sellers, since mainly the stubbornest are left. They may hang on until Tesla starts paying dividends, and the share price is much higher.
Any dilution argument would be falsified by the fact that the pie would be growing, despite each shareholder owning a lesser percentage slice. New money becomes an asset belonging to all shareholders.
In any event, Tesla inclusion in the S&P 500 may be more important to S&P and the index funds than to Tesla. But if fresh funds could be useful to Tesla's mission, and the investment banks are fair to Tesla and are able to sell new shares at a high price, then go ahead and ring the bell now.