I tend to agree with the first assessment.
I don't believe that cleaning with detergents or chemicalls does long term good for the engine compartment or underneath. I have no experience with salt, either road or sea. We live far enough from the coast that it is no problem. If there is a problem in your area that might change things on the under carriage.
Under the hood, numerous switches and unprotected metals do much better with a light film of oil than the harshly dry exposed position they get after chemical or detergent cleaning. We always locally clean any mess made from leaks and coat with a product like WD40 and leave it alone otherwise.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician