Do you really not understand the meaning of "argument" in the context of a political discussion of issues?
noun
1.an exchange of diverging or opposite views, typically a heated or angry one.
"I've had an argument with my father"
synonyms: quarrel, disagreement, squabble, fight, difference of opinion, dispute, wrangle, clash, altercation, feud, dissension, war of words, contretemps, exchange of views....
2.
a reason or set of reasons given with the aim of persuading others that an action or idea is right or wrong.
"there is a strong argument for submitting a formal appeal"
synonyms: reasoning, line of reasoning, logic, case...
When the term is used at a message board, it's usually the second definition.
Man: Oh look, this isn't an argument.
Mr. Vibrating: Yes it is.
Man: No it isn't. It's just contradiction.
Mr. Vibrating: No it isn't.
Man: It is!
Mr. Vibrating: It is not.
Man: Look, you just contradicted me.
Mr. Vibrating: I did not.
Man: Oh you did!!
Mr. Vibrating: No, no, no.
Man: You did just then.
Mr. Vibrating: Nonsense!
Man: Oh, this is futile!
Mr. Vibrating: No it isn't.
Man: I came here for a good argument.
Mr. Vibrating: No you didn't; no, you came here for an argument.
Man: An argument isn't just contradiction.
Mr. Vibrating: It can be.
Man: No it can't. An argument is a connected series of statements intended to establish a proposition.
Mr. Vibrating: No it isn't.
Man: Yes it is! It's not just contradiction.
Mr. Vibrating: Look, if I argue with you, I must take up a contrary position.
Man: Yes, but that's not just saying 'No it isn't.'
Mr. Vibrating: Yes it is!
Man: No it isn't!
Man: Argument is an intellectual process. Contradiction is just the automatic gainsaying of any statement the other person makes.
(short pause)
Mr. Vibrating: No it isn't.
Man: It is.
Mr. Vibrating: Not at all.
Man: Now look.