Yes. You are dealing with bad materials, ignorance, and bad decisions. There does exist, "self passivating" steel. When it starts to rust, the first coating of rust becomes the protective layer. There also exists CPVC or PVDC which is gray and survives sunlight. The thin stuff is called, DWV which means Drain, Waste, and Vent. It is not designed to survive any pressure. You can complain about the people cheating on materials for installation or rejoice about the money you get paid for fixing it.Yeah, down here most water pipes (old ones, that is) are made of galvanized (zinc plated) steel. And back in the day that sort of process was not a high quality one... the plating always flaked off. So many old buildings down here have leak problems.
Today, most houses are built using PVC pipe instead (although galvanized steel piping is of a much higher quality now), which I don't like either, because people tend to use the thin-walled glue-together type, instead of the threaded thick-schedule one. It breaks easily (for my taste) and is affected by the sun's UV when installed outdoors. Manufacturers say that they come with a UV protective coating, but I've seen those pipes being affected after only 5 years of laying in the sun.