It doesn't say who should be here. I liked it as a kid. I still like it. Its just saying it is unusual to see a Chinese man on Mulberry Street. The Raja is a bit over the top. Imagine Dr Suess "over the top". A Raja on Mulberry street may have been atypical in Suess's America.
Sure America is more multicultural now than when it was written, and more's the joy.
But the encouragement toward creativity surpasses the dated references or old Suessian fabulist, if dated references.