The closing and welding shut of the American liberal mind
I've seen conversations like that, both in person and online. Liberals have a white-knuckled grip on the "all opposition to Obama is racist" safety blanket these days; it's just about all they have left as his approval ratings plummeted during his second term. It's a pure expression of Leftist totalitarianism, a declaration that opposition to Dear Leader is fundamentally illegitimate. They're saying you are not allowed to disagree with the leader. You don't get to explain why you do, and they don't have to trouble themselves with responding to your arguments.
Needless to say, they'll go insane with rage if we ever have a black Republican President, and any conservative dares to play the "you just oppose him because you hate black people" card. Long before said President's successful campaign for office was completed, he would be ritually stripped of his blackness by the Left, so if 2017 rolls around and you find yourself sticking up for President Ben Carson at that dinner table, you will be haughtily informed that he's not a legitimate African-American.
The other thing that hisses between the seams in the welded-shut liberal mind these days is that Republican policies are an expression of hatred for whatever sainted group the Democrats profess to adore these days - from various minorities, to women, to the sacred Middle Class. They only oppose ObamaCare because they want people to die, for example.
I'm all in favor of being honest about the various ulterior motives of every politician, beginning with their desire to remain in office, but this argument is an expression of the infantilism of the liberal mind. They've regressed into spoiled toddlers, screaming about boogeymen in the closet. As far as politicians go, well, they all claim to be selfless servants of the people, but very few of them are. But among the ranks of the American people, how childish is it to assume that critics of ObamaCare are motivated by a sadistic desire to take away peoples' health insurance? That "argument" is the last fitful spark from a mental engine in the final stages of complete shutdown. And once again, it saves the liberal from having to engage with what his debate opponent is saying.
They were on better ground when they sneered that opponents of statism were greedy SOBs who didn't want to pay their "fair share." Of course, now that a fair number of rank-and-file liberals are getting their ObamaCare quotes and finding out just how much their "fair share" is going to be, that particular talking point is losing a lot of steam. It was always just another expression of totalitarianism anyway. If you think rational self-interest is a horrible sin, you must by definition believe that submission to the masters of the collective is the highest virtue.