Steel studs are not, and have never been, considered in the same category as structural iron - at least as it pertains to bonding.
Nor should they! The last thing we want os for somone to take the next step, and deliberately use them as a grounding conductor - as we already do when we bond a transformer to structural iron.
Metal studs may not normally be load bearing, but they're still structural and just as likely to become energized.
In many applications, they
are load bearing. Why should we consider them differently from one application to another just because of vertical load? Loading of the members makes no difference to the electrons.
