|Even the baby looks angry|
As the article explains, the term "middle class" means something very different in Brazil, as compared to the United States and Western Europe:
"the term is used broadly to include almost anyone able to pay rent, put food on the table and perhaps pay a monthly instalment on the refrigerator, microwave or television."
People making as little as $790 a month are considered part of Brazil's middle class, which would put them in the "working poor" category in the US.
As another article about the same topic from the New Yorker puts it:
"Brazil is an increasingly middle-class country that still has many of the characteristics of a poorer one."
Since workers with very low incomes rely on public services more than the upper middle class does, it helps us to understand why a rate hike for mass transit was such a rallying point.