Rather than saying the argumentative person needs to be "more" of something, I would say he would need to be "less".
Dude's an awful troll. If he wants to express his views, he should
present them in a less provocative/inflammatory manner.
(less) provocative Causing annoyance, anger, or another strong reaction, especially deliberately "a provocative article", "his provocative remarks on race"
(less) inflammatory (esp. of speech or writing) arousing or intended to arouse angry or violent feelings
A word that describes an academic and rational style of argument could be any of the following:
- objective (as suggested by Jon Hanna)
A Rogerian argument typifies the type of argument which we all should, ideally, aim towards.
A negotiating strategy in which common goals are identified and
opposing views are described as objectively as possible in an effort
to establish common ground and reach agreement.
Whereas traditional argument focuses on winning, the Rogerian model
seeks a mutually satisfactory solution.
... Effective Rogerian argument forces the people involved to listen
to each other and explore carefully all the options. It also downplays
emotional appeals and concentrates instead on objective
representations of the various points of view."