If it were the case that investors were participating solely to...

If it were the case that investors were participating solely to immediately flip for a profit the price would simply open at or below the cap raise price and the opportunity to take profits would evaporate, so it would be a pointless strategy. The reason instos tend to prefer investing in placements than buying on market is because it both provides them the liquidity to accumulate a large number of shares, and it helps with risk management by enabling them to enter at a discounted price. Then they accumulate the rest on market, driving the price higher. More often than not I've found in quality growing companies, the price moves significantly higher after a cap raise in the following weeks/months. There's typically a quick dip to the issue price, but investors quickly pile on sensing the growth opportunity that this additional cash presents for the company. Strong demand by instos to participate in the placement is also typically a dead giveaway that the price will rally after the raise

People just have PTSD from all the duds that raise solely to keep the lights on. A raise for growth is very bullish imo