[Tagging] The reason to not use loc_name is far too subjective.

[Dave F]

The wiki says this:
"but only where this is deemed to be too much of a slang name or 
otherwise unofficial-sounding. Ordinarily though, the name which local 
people use is the name we set in the name=* tag!"

https://wiki.openstreetmap.org/wiki/Names#Local_names_(loc_name)

This is, once again, poor quality tagging. It's far too subjective. I 
mean, what determines the cut off point for a name being too "slangy"?

If it's not on a road sign or in a street gazetteer database then it's 
almost certain not to have a name. If there's no recorded evidence & the 
name used is purely word of mouth in the local area, then it should be 
tagged using loc_name.

DaveF