I don't mind that. Let them spurt it out, then either explain or tell them to go away. Done like dinner. Simple. Move on.
Having a bone of contention (14th C – from the image of two dogs fighting over the same bone), on the other hand, is much messier because it involves having to work out some issue with someone else. Which necessitates (shudder) human interaction. It sometimes takes years to work out. People get stinky and spend time proposing resolutions that they know the other party is not going to accept, because they know they both have diametrically opposing viewpoints. But everyone does it just to piss the other party off and by doing so it allows them to complain to their followers that they have solved the issue but the other party is not facing reality. Everything becomes more entangled. Unless, the two parties should cooperate. But that never happens. No points in being agreeable. Set up an official task force who proposes sending it to a special committee complete with break-away sessions. Surely, everyone agrees, a committee will hammer out a solution. Meetings and retreats are planned. People argue over the seating plan and dates. Rubber chicken or mystery meat? Fit a day of golf in. Plan revenge should things not go their way. Get deadlocked. Break off talks. Appeal to the press. Reschedule talks. Repeat. Issue becomes lost in committee.
Everyone forgets what the bone of contention was in the first place.
Call in Bob for a song. Everybody likes Bob. Bob we can agree upon.