Welcome to Paradise song meaning

"It's about West Oakland, living in a warehouse with a lot of people, a bunch of artists and musicians, punks and whatever just lived all up and down, bums and junkies and thugs and gang members and stuff that just lived in that area. It's no place you want to walk around at night, but it's a neat warehouse where you can play basketball and stuff" - Armstrong.

The song is not only about a 'slum' that the author used to live in, it's also about leaving your parents' house. When you leave home and start a life of your own, you don't always get a house with 3 bedrooms and a swimming pool right away. In fact, most of the time you have nothing and have to live in some broken house with a bunch of friends. At first it scares you ("Dear mother, can you hear me whining..."), you panic and doubt you will ever succeed in this independent life you've decided to live, you think of quitting everything and going back home ("It makes me wonder why I'm still here..."). But people adapt to just about everything and soon you make friends and get used to your new living conditions. The new place becomes your home ("For some strange reason it's now feeling like my home").
"Some call it slums, some call it nice" - it's only slums when you look at it from a distance. But when you live and breathe it - it becomes nice because it is your home. Not your parents' home, but one of your own - and it's Paradise.