ATMega328p is old and obsolete. But the assembly language remains used in modern versions of this chip, such as the AVR DD or AVR EB.

Maybe ATMega328p is a more popular name that people aren’t using the “modern” chip names or “AVR Assembly”, but the code should mostly work on modern chips as well.

Hmmmmmmmm…

A collection tutorials for using assembly language on the command line to program AVR microcontrollers such as the ATmega328p microcontroller used in the Arduino.

The actual link shows that the author of the tutorials knows the difference. He says its an AVR Assembly tutorial (for example the ATmega328p), which is the correct way of presenting the information.