The short version is - if you’ve ever heard of infrared cameras that can see heat, that’s because everything glows based on heat. When things are very hot the glow is visible, but even cool things emit light outside of the visible spectrum. And emitting light takes energy, which means blackbody radiation (as this is called) takes energy (heat) away.
I’m pretty sure that’s a 4chan greentext, and I think it was even “Are you fucking sorry!?”. I also believe it was kicking a goalie in the face in a more outlandish scenario, followed by yelling that.
Snail mail is traditional mail, in this case presumably sending a physical data storage device for those terabytes of data, which could maybe be faster and more reliable than networking it.
Greentexts are popular outside of 4chan, good ones are often screenshotted and spread around. I don’t have proof that this is the actual original post, but here’s an image of the greentext on knowyourmeme: https://knowyourmeme.com/photos/2016597-greentext-stories