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It depends what the troll is trolling for. They aren't always trolling for arguments and they don't always have an abrasive personality. If that were the case, most trolls would be rejected and banned the first day they started bullying people.
What you describe sounds like stereotypical male trolls who argue about politics or enjoy wreaking havoc on internet communities. In reality trolls can be any gender or personality type, even if they don't appear to bully anyone on surface level. Sometimes they seem quite amiable and give the illusion that everybody likes them, even though they have subversive or selfish intent which most people will never see. Those people are called covert trolls.
Covert trolls may "troll" a forum they're otherwise unsuited to join. Perhaps they use an autism forum when they aren't really autistic, but they use that forum to "troll" for relationships with vulnerable people. When they engage with someone they may have no intent of maintaining a serious relationship but rather they do it like sport, for their own gratification or gain. They might love-bomb people or appear otherwise wonderful.
Behind the scenes they might be "trolling" for other relationships with other vulnerable people on the same site or elsewhere, again to boost their own ego or give themselves a white-knight sense of validation. Narcissists are known for trolling so they can boost their own ego by stealing other people's energy. It could be done consciously "I'm going to mess with that person", or subconsciously "I want that person to (love me) (like me) (flatter me) (support me) (make me seem popular)" even if they have no regard for the other person. None of this appears like bullying or antagonism, but the person is still a "troll" if they "troll" in hopes of receiving more than they'll ever give.
Picture someone trolling water in a fishing boat. They'll throw their bait into the water all day long, hoping a fish will bite. Their intention isn't to populate the water or help the fish. Their goal is to take as much as they need or even more than they need, while appearing to be Mr or Mrs Nice Guy for any oblivious passersby.
Here's the mentality of covert trolls who justify their own actions: