With price-discovery in the markets, the definition of "artificial" is vague. In one sense, the decline from 510 to 400 and below was "artificial" (if we assume it was, at least partly, a product of preknowledge of the coming attack and speculation that it would further hurt the price). In the other sense, the essence of markets is that all knowledge is taken into account, information is not perfect, and seldom even the best informed players have access to many information that some of the others have, in turn.
If we discount the last week downturn altogether, the price should be much higher by now. The attack failed - it could not damage the confidence towards XMR, it exposed the old scammers more, and proved how capable the devteam is. "Rolling back" the preparation of the attack from price history would lift us to 600 by tomorrow.
But if the market collectively decides that a selloff is in order, we might find ourselves at 300 instead. That some buyers openly like XMR at 400, is no more artificial than others vowing in the trollbox that they will sell every one of theirs, at whatever price they can get once the trading starts. Depending who will prevail, buying at 400 may be the last opportunity to buy at 400, or the last opportunity to sell at 400. Most likely, given the meager actual effect of the attack, it won't be neither, and anyone making decisions based on what others have already done, is just impoverishing himself as a result.
I have a largish number of XMR and BTC in the exchange, ready to react. But my reaction will be to buy if the price goes down, and sell if it goes up. This is my way of making slow and steady profit. Others have their way, and without panickers, my income would be significantly lower.