Those who call Mr. Popo a racist design are incredibly misinformed, and just looking for a rise out of people. They only echo what they've heard is controversial, but usually holds very little weight to the argument. A little research would educate that Popo is designed after Mahakala, a Buddhist Protector character of legend.
Toriyama pulled inspiration from tons of mythologies from all over the world to bring to life his wonderful stories. One example of a character with larger lips, is not a good argument either, when he's actually designed many black characters before and after that don't look like that, which shows that he has diversity in his work and always has.
Here is a character that showed up before Officer Black:
Some after:
And light skinned character with the same lip design showing it wasn't isolated to a black character:
