Stereotypes...the '80s, the predominant British influence, the fact that they were so unlike pop/rock of the '70s that they were lumped together by fans of the old school.
Middle America saw them as odd looking foreigners (or New Yorkers) who played a sound totally alien from their comfort zone of Skynyrd, Led Zep and Boston in some circles, Wings, Journey and Fleetwood Mac in others.
Punk rock and “new wave” (the latter of which the Brits call “new romantic” music) actually started in the USA. All the Brits did was inflate the same music with their accents and bands and send it back overseas. They actually got associated thanks to CBGB, who hosted both kinds of acts (e.g. Ramones, Talking Heads).
That is a fantastic explanation. Thank you.