Lots of American kiters are familiar with Mexico and may have not ever been to South America or to Brazil. Don’t assume that Brazil is anything like Mexico — because Brazil is not much like Mexico at all!
Mexico pros: closer to the U.S., more Americans know a little Spanish vs Portuguese
Mexico cons: not as friendly, much less interaction with locals, more likely to get cheated / have to deal with corruption first-hand, less territory accessible, infrastructure not as good
Brazil pros: much more friendly and much more interaction with Brazilians, much bigger country, better infrastructure for kiters, more international visitors, warmer, more reliable wind, better hotels, more cosmopolitan/diverse culture
Brazil cons: farther from the U.S.