The results of some extensive field research….
“I’m just trying to find some common ground / consensus / understanding on this issue.”
From context alone, this appears to me to be be part of some kind of mating ritual. It usually follows displays of aggression. It may be an attempt to appease a potential mate, or display to rival males that the male thinks the female is already taken. In neither case does it ever seem to be effective and it possibly an obsolescent strategy from a remnant of a larger population.
“That’s an interesting point you have made.”
Once again, this often follows displays of aggression, but it’s meaning is obscure. It may be some kind of primitive defense mechanism in which the right wing subjects pretends to have forgotten they are in an argument with someone who dislikes them. Alternately, it may indicate senility.
“It’s just commonsense.”
In some cases this is an evasion strategy to avoid further argument, although more commonly it is used in an attempt to strengthen a weak, poorly argued position, by declaring it to be a commonly held view among right wing people; i.e. a circular argument. In this sense it is akin to saying “my family have been dying of lung cancer for generations, so smoking is obviously a good idea.” Frequently recorded in individuals with mild brain damage.
“You just don’t know what you’re talking about.”
In all recorded cases, the right wing person appears to mean “my upbringing and life have somehow given me more knowledge and life experience than yours have given you.” No reason is ever given why. The subjects’ lifestyles range from rural to poor inner city to upper-class suburban, so there is no apparent correlation between them and the meaning of the statement.
‘My people have been in this country since 183o.”
Once again, the basic meaning is simple but the idiom is hard to decipher, as there never seems to be any correlation between the subject matter of the conversation and the decision to include this statement. Similar statements like “I worked my ass off for years,” “never got no handouts,” ” etc, also appear to be essentially meaningless and form no functional part of the argument the person is making. They may be the right wing equivalent of “um”, or “er”.