Of course it costs nothing to address people in a way that they feel comfortable with, so you should do it. But, in a Postel's law sort of way, in terms of critiquing argument I don't think it's worth dwelling on the tone. Two plus two is four no matter how many times the person arguing it uses the word "fuck", to put it crudely. And often, addressing tone is a way of eliding real argumentation.
> Of course it costs nothing to address people in a way that they feel comfortable with, so you should do it.
It doesn't cost nothing, it's costs a lot of time and attention to find out what they're comfortable with and much attention to filter yourself to to fit that, so no you shouldn't just do it without a good reason.
Maybe it is and maybe it isn't, but you assume it's a choice and that's a mistake. You presume it's easy to know how people want to be treated, but there are a great many conditions that make reading other people difficult for entire classes of people. They aren't necessarily being miserly, they may be doing the best they can and that's all they've got. Those with Aspergers for example have to do with intellect what most people do instinctively socially speaking, and that's exhausting for them; they simply aren't wired to be social.
