There's no such thing as being "dogmatic SSPX". All SSPX members capable of using their common sense know that a Traditional Latin Mass, no matter who celebrates it, is fully valid and acceptable. Those in the SSPX who are closet sede I doubt will be judged by God in a different way. You need to realize, Myrna, that God will not judge someone based on whether or not they thought the Pope was Pope, and if not why they didn't publicize their viewpoint. There has never been any evidence to show God punishes those who are not sede during the reign of a questionable Pope. What matters is being Traditional Catholic and doing all the things (attending Mass, making penance, repenting for past sins, etc.) that help your soul obtain Heaven.
Regarding the article, I agree with it that sedes should not treat SSPXers as schismatics.