Overvalued is in the eye of the beholder, in this case the market. There were people willing to buy the stock at that price, why not sell it to them? If the buyers really believed it was going "to the moon", then you could just as well argue they cheated a lot of potential buyers out of the chance to get in on that action.
Finally, if you do think it's overvalued, arguably the best thing to do as a company is sell more stock, to maximize the amount of money per share you get. This is the way Tesla does it for example: they only sell more shares into the market when the stock price is particularly high.