As a Brazilian this is accurate to what girls wear here

Huh. The Brazilian t-shirt is showing Jesus - as depicted with the famous Brazilian statue - standing right in the middle of the US.

"Brazilian Miku, but she’s… you know…"
A lot more White? And Christian?

What did they meme by all this...?
[edit] Having looked at the artist's other pictures, yeah, there's no point to such jokes here, because you can't joke about these things when they are so explicitly intentional. I feel a bit embarrassed to have tried, now.

Can confirm, fellow Brapilian here, this is the most accurate depiction of a Brazilian MIku i have seen until now.