Thread:KingCannon/@comment-7218858-20170706023832/@comment-25501246-20170706190708

Because Akira Toriyama drew that, and acknowledged it into his Dragon Ball work. Same with Dr. Slump. Illegals is written by someone else, which alone makes it not the same thing.

Many wikis take the stance of "Non-canon until proven otherwise". That "proven otherwise" bit is done by the author, either indirectly (inserting the stuff in his main work) or directly (stating it).