WHY THEY'RE BAD
Corporate raiders insist they're looking out for the shareholder by forcing the managers to focus on increasing the value of the firm. If a company's share prices are high, it supposedly reflects well on the management of the firm; if the prices are low, the shareholders presumably would benefit from the takeover battle and subsequent change of management.
The flaw in this argument is (a) shareholders are not the only stakeholders in the corporation; workers, neighbors, and consumers also have interests that deserve protection; and (b), the impact of the corporate raider on FUTURE shareholders is inherently damaging over the long run because the targeted corporation's share prices are driven to a higher baseline anyway. After the takever battle between the raider and management, FUTURE buyers of the stock pay a higher price but are stuck with stagnant share prices because further increases don't make economic sense.
If the leveraged buyout succeeds, the company is saddled with debt in excess of its book value, which imposes an extreme burden; if it fails (greenmail), then company is still saddled with immense debt.
He usually quotes Ayn Rand bromides about his adversaries being moochers and wreckers, but he destroys the livelihood of thousands, and he makes his fortune through ambush.