It is expressly disallowed in the O'Reilly copyright statement. What's more, some of the authors of those (and other O'Reilly) books mentioned are known to be strong contributors to the Perlmonks site's daily activity. They don't deserve to have their copyright violated, and their intellectual property freely distributed without permission, and without compensation.

Such sites pop up from time to time. And not surprisingly, such sites disappear from time to time as well.