If there's anything Rush Limbaugh is an excellent example of its hypocrisy--calling for harsh sentences for drug offenders, while sending his maid to buy Oxycontin, and so forth. At the end of the day Rush is just a hustler, who will do whatever it takes to jerk peoples chains, because there is a market for it.
If only Rush was actually the sole person (there rarely is one person) representing the GOP. While many people appeal to Rush, there are also a number of people who find that sort of thing revolting, and if Rush Limbaugh did represent the GOP, it would guarantee the Democrats victories for quite some time.
All the energy the Rahm Emanuel, et al are using going after Rush Limbaugh is a wasted effort. This effort is going to backfire, and besides there are many more important things. If the Democrats wanted to attack the Republicans on something it should be less about who represents them. Democrats railed against GOP attacks on character, and returning the favor lends itself to charges of hypocrisy.
A better move would be to attack the Republicans and its ideas, or lack thereof. What exactly does the Republicans stand for? Forcing the Republicans to defend the Reagan ideals, which have become clique would put the party in a tight spot, but so would forcing the party to come up with real alternatives. Don't like what's being put forth, fine, come up with an alternative.