We've already explained this to you... we talk about them because they're, by far, the two best conferences. The Big East and the ACC will produce 3 of the 4 #1 seeds and the 3 favorites to win the Championship. Plus, the VAST majority of people are from the EAST, where the Big East and ACC are and where the most popular teams play -- UConn, BC, Syracuse, and Duke. People are going to talk about their teams and conferences first and foremost.
edit: If we only talk Big East... then what do you call mine and MC Hammer's Gonzaga bashing?