About a nine months ago, I outlined a strong media/political basis for Republican obstructionism (too lazy to dig out the old post.)
It runs something like this. A national sense of political chaos will be psychologically attributed to the president in power whether they are responsible or not. Even more than a sense of gridlock, it is a sense of hostility and partisanship that does the damage as it becomes psychologically associated with the the most visible figure (Obama) so that his mere image tends to bring forth the unpleasant associations of conflict.
So, the screaming isn't about any particular issue or objection, it's about creating a mass mental environment which associates negative feelings to Obama's image. The continued tension and hostility are the effective message.
The beauty of this is that the people doing the screaming don't take the majority of the hit because their individual media presences are so much lower.
The broader environment of hostility, resonating with economic stress, creates a broader sense that something is wrong. That sense that something is wrong automatically associates with the President, not with the less defined figures of the minority.
This is one of those things that talk radio and FoxNews are great for. It's not about any one complaint, it's about the long sense of tension that their individual daily activities generate.