A more cynical reason: Even if there ends up never being a baby in the tub, it's still far better to have the bathwater there than all over the bathroom floor, dripping into the walls, staining the ceiling, etc.

One of the less attractive characteristics of the carousel ATMer (the bathwater) is the tendency to want to short-circuit the scientific process and claim their pet idea as having widespread "support" far, far too prematurely. This, unfortunately, caused confusion (particularly among those too new to the board to be familiar with the "usual suspects"), particularly when ATMers would camp in Q&A-type forums solely to promote their ideas.

Those who are proficient at training pets and raising children know that it's far easier to redirect a behavior to an acceptable outlet than to forbid it outright. ATM is restricted to the ATM forum and is thus labeled fairly clearly. Those reading it know to take the appropriate precautions.

__________________
And you, to whom adversity has dealt the final blow
With smiling [faces] lyin' to ye' everywhere ye' go
Turn to, and put out all your strength of arm and heart and brain
And like the Mary Ellen Carter, rise again.