First time I have ever come across an electrical cable inserted in a hole drilled in bottom of joist. I am sure the “2 inch minimum clearance from edge of joist would apply here”, would just like to verify that. There was no visible exit from joist so who ever drilled the hole must have gone through it completely.
( just to clarify, cable at left is not the same as in bottom of joist )
What exactly is your concern? I bet the cable goes up through the floor into a wall above the joist/beam.
Cheers
Is it a basement or crawlspace or other? 
Welll my concern would be as this is a structural support beam in basement that one of the beams has been compromised by drilling a hole from top to bottom. This reduces size of beam and load bearing capacity and also maximum span distance. Beam would be rated at roughly as 3 1/2 joists compared to the 4 joist ( at 1 1/2 inches ) beam it started at.
The NM cable is not protected especially if they finish the basement.
Well I kind of think you are overthinking it. Can’t really imagine a 1/2 inch hole would, in any way, compromise the beam.
I suspect one of our SEs might offer an opinion. You could PM Randy Mayo he will answer better than me.
Cheers
I have no problem with it , but why ?
Just because the dumb ass wanted to drill a hole?
It makes no sense to me.
Don’t make much sense, but there is no doubt in my mind that little hole is going to affect that 4-ply beam.
As Larry said, protection plates should be added so some idiot decides to finish the basement.
To make code compliant:
Remove staple. Install a running strip, 1 x 3 (or 1 x whatever), between the NM and the joists then secure NM to running strip.
Plumber: you mean I cannot cut those? 
Electrician: it’s just a small hole! 
Inspector: you dimwits! there are special rules you have to follow when you drill in framing! 
The wire goes to a switch at the top of the stairs. Yellow arrow.
