why would I need java script turned on?

The Internet won't function as you expect without it. Such as the black menu bar at the top of every page here.

Java and JavaScript, despite the similar names, have nothing to do with each other.

peregrineguy wrote:

brand new MackBook Pro. Updated Monterey.

I thought recommendations are to leave it off for security purposes.

JavaScript is the third layer of standard web site technologies: HTML, CSS, JavaScript.

Turn it off and compare your results if in doubt...

It is programming language used both on the client-side and server-side that allows web sites to be interactive and dynamic:

few example—

dynamic updating content

control multimedia

animations

Show or hide more information

Change the color of a button when the mouse overs

Slide through a carousel of images

Zooming in or zooming on images

Displaying a timer or count-down

Playing audio and video

drop-down menus

Change Security preferences in Safari on Mac - Apple Support