Wanna give my two cents here.

Green Day caught a lot of shit for not being an “authentic” punk band.

Green Day has real chops has a punk band, doing everything DIY in those early days, their first few albums are full of incredibly well written songs. That’s what allowed them to break through into the mainstream and introduce the whole of suburban America to Pop Punk in a way that hadn’t previously been seen before.

Incorporating aspects of the Ramones, the Descendents, the Buzzcocks and the Adolescents into their song writing, anyone who thoroughly enjoys punk can immediately see that Green Day had a real affinity for punk music. Their songs are catchy and instantly recognizable.

Green Day’s early music sounds like true SoCal punk rock to me and I understand how anyone could think otherwise.