I was never goth myself, couldn't really get myself up to go to the clubs, but from chats with goth friends and listening to things they liked, my conclusion is that goth music is whatever goths like to listen to when they're hanging out together. And back in the 80s that very very much was inclusive of The Cure.I'm a huge Cure fan and have been for 30+ years. I'm the type for whom "the real Cure" is in the early albums, with Pornography, Faith and 17 seconds at their pinnacle. So, it's not that I'm looking at songs such as Friday I'm in love and thinking "Hey, that's not dark at all!"
Even so, I don't see them as goth.
And, hey c'mon, you know what Robert Smith looked like back then, right?
For all I know goth kids these days might not even have time of day for Bauhaus and Souxie because they're too busy enjoying the multitude of Japanese goth idol groups.