I was a roofer for a few years. In Florida, a state with some of (if not the) the most strict roof codes in the country. It’s perfectly ok to layer shingles like that and was common practice for a good while. I’ve torn off houses with 4+ layers of shingles several times and had the decking be just fine underneath them. You have no idea what you’re talking about
Ah, fuck! My ideology will never recover from this!