A point refuted a thousand times, commonly abbreviated PRATT, is a pithy way of dismissing... exactly what it says. If there's no God, why is the banana so well designed? If the Earth is round, how come the horizon is flat? Jet fuel doesn't burn hot enough to melt steel? Yeah, we could go over this one more time, but let's not.
Whether it's a result of the Eternal September or a particularly artless form of sealioning, one way that people argue interesting but sanity-free points on the internet is to argue them at a very low level, but argue them often. PRATT is a simple way to communicate that you are not buying this argument, and not taking the time to argue it.
As should be apparent, if you state that something is a PRATT, the next thing to do is walk away. You shouldn't indicate that you aren't going to argue about this, and then argue about this. Whether you use the acronym or a well-phrased paragraph, this is a statement that you need to back up with action; continuing to engage on the same point is the same as validating it as worth going over... again.