My Moto X Pure received 6.0.1 last year.
I received the 6.0.1 update by performing these steps:
Power Off phone
Remove SIM card
Power On and connect to Wi-Fi
Check for update
Install update and allow to reboot.
Power Off phone
Put SIM card back
Power On.
No, you did not... the Moto X Pure (XT1575) never got 6.0.1, it wasn't even trialed, beta'd, or soak tested. It doesn't exist.
The latest official software for the MXPE is MPHS24.49-18-16 which is Android 6.0 with a December 1, 2016, Security Patch update date, and was released in February 2017.
Some, but not all, Moto X Style (XT1572) variants got 6.0.1. Although the Chinese Style variant (XT1570) never got beyond 5.1.1.
Although I am going to give you the benefit here and say you're just mistaken, because I know you from other forums and I you clearly have a Moto X Pure Edition, so it must have been at 6.0 if it was stock.