Typical crank behavior. "They don't believe me because of The Conspiracy, not because my theories are faulty!"
Or maybe they just think he's wrong.
Bingo.
No matter how weird or unconventional his theories, if they were self-consistent and explanatory, he'd have no trouble getting people to admit he had something interesting. Relativity and quantum theory were both completely bizarre and contrary to orthodox theory when they were introduced, but had no problem finding converts, because they *worked*, and no holes could be found in them.
Perhaps you are unfamiliar with how cranky Sir Isaac Newton was when it came to discussions of "his" calculus. Without getting into any defense of João, I wouldn't write him off merely because he was a bit testy, especially where it concerned the journal Nature.
--Boot Hill