I kinda wish the Catholics could present a better supported doctrine concerning purgatory. Perhaps they can, but the article you presented didn't.
For example, I can support the trinity or incarnation with tons of scripture...as I assume you can too.
1 Cor 3:15 as if through fire sounds more like...by the skin of your teeth. As that individual hasn't done much for Christ in their life. Their works will be burnt up and receive little reward. This judgement is called the Bema Seat Judgement or the Judgement seat of Christ. They are saved and will not experience the Great White Throne.
1 Peter 3:19 seems to be talking in subject to those who perished prior to Noah building the ark...and doesn't seem to mention anyone else. There are several opinions on who they just might be.
I wasn't trying to get into a debate about purgatory but was looking at it in a means as how it pertains to hell. The article made it sound like purgatory was only for believers who were not fully purified, what ever that means, as I believe all believers are given the righteousness of Christ when they are saved.
Those who are not believers don't seem to have this "second chance" so to speak and will spend eternity in hell.