Yes, we do have names with "anger", like Zbigniew. But the truth is that most of the names from this list come from Middle Ages and actually don't exist anymore.
I don't think "jaro" means "spring"; an adjective "jary" means "fierce" in some Slavic languages, so Jarogniew should show a "great wrath" to his enemies, such as Casimir should "destroy their peace" (see CASIMIR). Names like this are an inheritance of a time when the Slavs were ferocious warriors.