I don't really understand how this "poison pill" is legal. Imagine that you own a stock that can be sold at free market at $10/share. Then the board decides that whoever buys those shares will have to resell them to board members at $1. This means that now the price of those shares drops to $1 and you have lost $9 per share. How this can be legal?
Now, you may argue that it is in the best interest of the shareholders to allow the hostile takeover to go through, but it appears that the strict mechanics of the poison pill do not immediately hurt shareholders.