Dictionaries define anime as "animation from Japan", but in practice it refers 99% of the time to an artistic style descended from Tezuka. This logic accounts for the questioning of Big O, the consideration of Avatar as anime, and partially the questioning of Speed Racer.
The rest is "shitty dubs/shows I don't like don't count as anime" trolling. When looking at the characters and the plots, its absurd. and if Sailor Moon and DBZ couldn't be so censored to no longer qualify as anime, the mild americanizations and shitty jokes don't disqualify Pokemon and Digimon, which leave the original scripts largely intact. (Speed Racer, on the other hand, as opposed to Mach GoGoGo, is genuinely questionable on these grounds.)