We know that when scholars discuss and debate the Torah they put forward a range of interpretations. Sometimes their arguments become heated and noisy. Unpleasant scenes take place. Ugly things are said.
What happens next? In some cases the dispute dies down as quickly as it arises and the disputants remain firm friends regardless of their differences.
This is the kind of controversy that Rashi is referring to in his discussion of a passage in Kiddushin 30b, when he says, “A struggle that revolves around the Torah ends in love”.
In other cases the stability of the whole community is affected and the wounds never heal. Years later the conflict is still going on even though no-one might clearly recall what caused it in the first place.
Moses feared that the problems caused by Korach might go on for ever. The leader’s task in trying to manage a large, unwieldy people and weld them into one could well be exacerbated and the whole future might be jeopardised. It’s not that everyone is expected to agree on everything (the first Viscount Samuel used to say, “A nation without controversy is politically dead”), but disagreement should be carried out agreeably and with respect and forbearance shown on both sides.
That kind of controversy is exemplified by Bet Hillel and Bet Shammai, who had opposing views on over three hundred matters but loved each other nevertheless.