Paint is a cop out. In that situation, the regular expansion and contraction wears the surface, leaving it susceptible to water.Ill let all the structural engineers know your concerns and all your buddies that can not apply a couple of coats of paint.
All external steel, especially structural should be at least galvanized, and if necessary a slip plane fitted.
Yes, it's convenient for a builder to pick up some cheap angle, put a coat of gloss on it, only use 75mm or 100mm so they don't need to remove so many bricks, and then leave the customer to deal with the problems in a few years time once the builders guarantee (if any) has expired.