While I think breck's phrasing is a bit overstated, and sometimes you really do want to have two contrasting clauses in a single sentence, their statement was (I presume intentionally!) self-illustrating:

> I respect your comment but you can ignore the left half of any but comment.

"I respect your comment, but..." isn't doing any meaningful work in this sentence; it's not contrasting anything, it's just introducing the actual point: "You can ignore the left half of any 'but' comment." You don't really lose anything by taking out the left half.