Mostly because it isn't libre.
Perhaps a controversial opinion, but I quite like Mailspring as a desktop email client. It looks and feels much more modern than Thunderbird or Evolution.
I guess Donald Rumsfeld was right.
Arch on ARM? What kind of device is this?
Today is a good day for coffee!
Do you mean from a historical standpoint? It depends on the culture, but it's pretty recent in its current iteration — in the west, it followed the rise of Christianity. For much of western history at least, it was considered OK to pitch, within reason (manly!) but not to catch (effeminate!). Warring states China was pretty similar. I'm less familiar with India but in any case that would have been suppressed by the Mughals.