Why do liberals prostrate themselves before the conservative media?

This question was triggered by an earlier Diary that mentioned Lieberman's appearance on Don Imus' s program, as well as Kucinich's refusal to appear on Hardball.  Why do liberals, or Democrats in general, feel the need to legitimize conservative media by appearing on these shows.  It's one thing to appear on MTP with Tim Russert; while his audience may be somewhat small compared to "American Idol" or "Friends," it can set the political agenda for the week. The reach of Imus or Hardball, or any other various cable shows is laughingly limited, so what's the rationale?  Are they THAT influential?