The main issue is that it is incorrect. Just because tagging it incorrectly won't cause any major navigation issues doesn't mean it's not correct. I could tag all of there warehouses here as supermarkets and they would still appear on the map and can be accessed by routing systems, but that doesn't mean they would not be incorrect. 

It should not be a trunk road because it, by US definition, does not serve as one. In a suburban area like this, a trunk road is defined by the OSM Wiki as "the most important non-motorway roads that provide main, long-haul connections between population centers of regional importance". This here is a simple connector road between an Interstate and a relatively minor arterial road. It still does not make sense to me why such a short access road should be placed higher in the hierarchy than the road it leads to.

Tagging roads as different "colors" just to specify pedestrian access rather than for how they serve in the highway network would be tagging for the renderer. (https://wiki.openstreetmap.org/wiki/Tagging_for_the_renderer) I explained how to properly specify pedestrian access here without changing the tags of the road itself.