Yes, I often get "bored" when I can't refute a point, too.
I mean let me point out I wasn't the one who thought that this needed such a degree of discussion. I made what appeared to be and still is a prima facie argument which for whatever reason you two decided needed to be challenged. You have been unable to provide reason why it shouldn't
Instead, you resort to playing off of "those socialists and their shifty motives" and in fact argue that the socialists who identify as socialists are "extreme" socialists, and therefore not reflective of what the majority of "true" socialists believe. What the heck is a "non-extreme" socialist, then? No true scotsman.... err... socialist.... after all. No, you are trying to delineate distinctions where none exist.
I'm sorry, I feel ill-equipped to answer your example. But if this person doesn't believe Christ is God's son, only an important figure, and if a vast majority of Christians say he's not a Christian, then yes, I'm reasonably confident saying he's not a Christian. In fact, what you've described sounds to me a lot like what we call a "Jew." It's not absolute, but in the absence of other evidence its weight cannot be dismissed.
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Look it seems like I've made a pretty simple general and specific case argument here:
The general case being that the state of a person's membership to a club can most often be determined to a reasonable degree of certainty by the consensus of that club.
The specific case being that since socialists reject Obama, Obama is probably not a socialist.
You seem to be attacking both the general and the specific cases. Your attack on the general case is dependent on a hypothetical 'psuedo-christian', or perhaps some other equally rare example. In other words, you are thus far unable to provide commonplace real-world examples of why the group's consensus should be dismissed.
Your attacks on the specific case are rife with special exceptions for socialists - implying without support that they behave in manners not typically seen among other fringe political groups.