If folks take note of your observations, but elect to...

If folks take note of your observations, but elect to participate anyway, that doesn't necessarily mean they are fools. It can mean there are other factors in their decision.

Your portrayal as a "fools bargain in the aggregate" ignores the fact that different shareholders have different situations, therefore different criteria for buying (including participating in rights issues) or selling.

The market as a whole - just like individual companies - relies on different investors having different criteria for investing. For every completed transaction, there are two participants, who have made a decision - and presumably each believe they have made the right choice at that time. For every seller who believes selling was the right decision at that time, there is a buyer who believes buying was the right decision. Similarly, for every company (board) that believes they benefit by issuing share rights there are investors who decide they benefit by participating.