It makes no sense for Kyle to let himself be persuaded by his father to take over the trolling for him. All Gerald has done to persuade him is insult Kyle and everything he believes in.
When Kyle confronts Gerald about being the troll and Gerald orders Kyle to keep trolling for him, it makes no sense for Kyle to ask "How?" It implies that he agrees to doing it. Gerald's arguments for doing that have not been persuasive by this point, at any rate not to Kyle who has a moral compass. If anything, Kyle should at this point be asking "Why?" (or refusing his father's request outright.)