It also says in tutorial I can hookup without the level shifter
It's talking about the backlight.
(Arduino Uno has 3 v pin so why not)
Because the Uno GPIO levels that you are going to connect to the display are at 5V.
I have tried reading various other tutorials but everyone seems to use some sort of chip.
And rightly so. There are other ways to translate levels but an IC offers guaranteed equal propagation delays for all its ports which is important when you're translating the levels of a data bus.
You really should get a level shifting IC...