This tit-for-tat has been going on for a long time. Brazil, at least in 2000, made you jump through all kinds of hoops for a simple tourist visa and the cost was pretty steep- maybe $60 or so? That was what we did to Brazilians wanting to enter the US. When DH and I went to Russia in 2003 there was a form he would have had to fill out if he were under a certain age (he was 65 so not necessary) about whether he'd fulfilled any military obligations. It was because so many young Russian men tried to leave the country to avoid military conscription that that's what we did if they wanted a US visa. Sadly, for countries such as Brazil, where they need the tourism, it can just lead tourists to decide to go elsewhere.
I'm glad I'm exempt from the $7 due to my age but it wouldn't bother me to pay it.