Everyone builds a strawman caricature mildly similar their opponent. Assign the least appealing policies and ideas to such and opponent, and then ignore and dismiss any explanation that the real guy gives to why he is different than the made up caricature.
As a result, we rarely talk about the merits of any policy, just the demerits. And only in the echo chamber of our own camp. Because really, who wants to hear their guy slandered? Lets just change the channel to the other side — Fox tends to slander the left, while MSNBC and to a lesser degree CNN tend to slander the right.