Okay so honestly I get a lot of crap online when roleplaying or just talking about something, and people think they can get away with a lot of shit, especially when hidden behind a screen. Now you too can counterattack and be a bad bitch in these simple steps-
1. Make sure your grammar/spelling is correct.
Be mature in an argument, that's the least you can do for people to take you seriously. And, if anything it proves to them a good few points, which you can use to counterattack as well.
2. Have proof
In order to defend your bias, you'll need sources, most likely from somewhere reliable. Even if you're unbiased on a topic, you'll need to advocate for both sides as equally as possible.
3. Don't be afraid to be wrong or correct yourself!
Still, don't go being wrong on purpose and making a fool of yourself. Correcting yourself or admitting your faults is pretty damn mature if you ask me. Don't stray from the topic, as that's what a lot of people do when they realize they're on the loosing end.
4. Don't be an asshole.
If someone has a particular opinion that doesn't hurt or disrespect anyone else, leave them be! It's one thing to be a complete troll or dick, but it's another to just have different ways of thinking.
5. Stopping
If the other person is being an ass for no reason at all or is just what I'd call 'slow minded', don't waste your time on them. Block/report/stop arguing with them if things get really bad and use it as a counterargument as well, don't waste your time on stupid people!