I would love to see the code reference to back up the inspector's request. 110.24 only refers to conductor terminations, and I have a really hard time believing that steel and copper with have a galvanic reaction when miles of copper plumbing is strapped with steel straps all over the world.
There is virtually no current alon this path under normal conditions, either.
Do a Google search of electrolysis between steel and copper. Here is a cut of a thing I found in the first 2 seconds.
THE GALVANIC SERIES
1. Aluminum 7. Tin
2. Zinc 8. Lead
3. Steel 9. Brass
4. Iron 10. Copper
5. Nickel 11. Bronze
6. Stainless Steel 400 12. Stainless Steel 300
Series Series
When any two metals in this list are in contact, with
an electrolytic present, the one with the lower number is
corroded. The galvanic action increases as the metals
are farther apart in the Galvanic Series. It is not always
true that there is greater corrosion the further down the
scale one goes. In certain cases one metal immediately
following another may be very corrosive.
The code does require corrosion prevention. I have never been allowed to lay my EMT across a copper pipe in the ceiling, without putting a dielectric between them.