It's likely to make the average Western onlooker rather uncomfortable because of the genre's history...
a history that would be largely unknown to a Japanese onlooker. Popo is undoubtedly a product of this: even though he isn't a human in the context of the series, his origins seem quite obvious.
Japanese blackface, one could argue, doesn't carry the connotations that made the Western version so vile.
And yet, at the same time, it does, at least to us.
Let's start with blackface, then, since it's already been mentioned.
'Blacking up' for theatrical purposes goes back hundreds of years, and was an established practice in Shakespeare's day.
Many early cartoons from the likes of Disney and Warner Brothers readily incorporated this imagery into their output, which has since resulted in rather conspicuous gaps in their modern-day re-releases.