Run your meetings / classes according to Roberts rules, move to set out a time limit for each person to make their point, limit each person to 1 rebuttal, and then vote on the issue.

Whenever I had to deal with contentious issues as a chair of a meeting this is exactly how I proceeded, much to the dismay of the people who wanted to argue all day.

The people who cause the most issues usually take their rebuttal early and then the debate can proceed amongst the more reasonable people.