"The recent war" (1991-1995), or Croatian War of Independence, was a mess and things like that happened. It doesn't mean anything.
In Croatian schools, they always say Tesla was Serbian and born in Croatian territory. Both Croatians and Serbs are proud of him, I guess.
As for mutual hatred, many people lost their families in the war, and obviously many Serbs were part of the aggression, so the relationship is no wonder.
Anyway, the article is great! Just what I needed.