Okay, that's a start. Lieberman ran in 2004; his
main opponents were John Kerry, John Edwards, Wesley Clark, Howard Dean, Dennis Kucinich and Dick Gephardt. (Al Sharpton, Carol Mosely Braun, and Bob Graham were also announced candidates.)
Can you recall which one(s) you think made the comments you think you recall hearing? Can you recall whether the comment was made during a debate, in a campaign ad, at a press conference, at a fund-raiser, anything at all?
It's quite possible such a remark was made. It's also quite possible you're misremembering. If you can provide some additional details, it may jog someone else's memory. If such a remark actually was made, it's likely you're not the only one who heard it, and it should be possible to track the comment down. (Especially if, as your comment implies, more than one candidate made such a remark.)
Okay, that's another start. Clinton's
main opponents were Jerry Brown, Paul Tsongas, Bob Kerrey and Tom Harkin.
Again, can you recall which one you think it was that used "moderate" as an insult? Can you recall in what context you think the remark was made?
Yes, I do. Memory is often unreliable, so I'm not willing to take your word that you are are remembering what was said correctly.
If this kind of comment was
common in presidential primaries of both parties, as you assert, then someone should be able to come up with examples. The more details you can provide, the easier it should be to track these examples down. But until such examples can be tracked down, your claim that such comments were common in both parties remains simply an unsourced claim.