There’s a lunch spot at the top of the T but I have to cross the stem of the T to reach the top of the T.
Why are they doubling my chances to get hit when they could just add another crosswalk and let me cross one street instead of two? Are they stupid?

Yup, a diagonal crosswalk is part of a “pedestrian scramble”. Someone posted the wiki article elsewhere in this post.
Sure but you can’t be the only ones doing it. It’s safer to be predictable and visible, follow whatever the local conventions/regulations/laws are
The scramble is a formal design convention, requiring lights, signage and markings, it’s not a YOLO pedestrian manuever.