Sometimes strongly-opinionated people (such as myself) are misunderstood as “arrogant”. In the end, you need a lot more information and context on a person than just a few of their paragraphs to judge that. I’ll say though that arrogance and lack of empathy go hand-in-hand, so that’s one way to tell if they’re arrogant.
Either way, if you give people permission to troll “arrogant people”, then you are telling them that it’s okay to judge others before you know them. And of course that’s the source of a ton of society’s garbage. Not to mention everyone’s always in the process of learning and maturing. Nobody’s perfect; and to be an ass to others is hypocritical, even if the area you’re judging them for isn’t the one you struggle with yourself.