The word argument comes from Old French arguere which in turn comes from Latin argūmentum and means - to make clear. I see nothing weak in an argument in the sense of a logical sequence of statements to justify a position or conclusion. But argument in the sense of quarrel means that control of a situation has been lost and in that sense then yes it is a weakness.

Argument is persuasion, the ability to influence the thoughts of the other person and to steer that person in the direction you want. This seems to me to be a natural and necessary tool for a dom.

I don't know who said that arguments are a weak man's weapon, sounds like the sort of thing a person whose only method to resolve difference is force would say.