I don't think there is a bigger gap. I think there is a HUGE difference in the level of civility ................... much of it driven by the anonymity of the internet/email forwards and the need for ratings/booksales.
People used to fight duels and have decade long bitter feuds w/ better manners than many modern folks use to converse about minor political topics.
your right. go look at say think progress and media matters compared to say newsmax and redstate. huge huge huge difference. oneside is hellbent on smearing those with whom they disagree while accusing others of doing the smearing.