(Why do they have to disable commenting on all blogs AND forum threads that haven't been commented on in 30 days? I don't know how turn that on or off in wikis I'm admin of but as off is the default, I don't have to.)
Anyway, the old forum thread was asking how Frieza became Mecha Frieza again for his imprisonment in the cocoon when he was in his original fourth form as seen in the Saiyaman and Kid Buu Sagas
I have two possible explanations for that, go which whichever you want
a.) It's only canon to Kai, as it was written by Akira Toriyama to continue the series between the fight with Kid Buu and the final scenes, and Kai is completely loyal to the manga with no filler (from what I heard, hell is never seen in the manga, the only two areas of Other World ever seen in the manga are King Kai and Supreme Kai's planets, though in the manga it's said that the souls of the damned have their bodies and memories erased)
b.) It is canon to the main series, and when they moved Frieza to his own personal hell to suffer for his crimes, they reverted him to the form that he died in as a reminder of it. Which wasn't necessary the second time because he died in his unaltered fourth form. They'd also have to erase his memory because he witnessed the entire fight between Goku and Buu, where Sorbet had to tell him that Goku beat Buu, causing Frieza to slam his tail on the ground and realize he needed to become much stronger.