Societies need tolerance to continue peacefully, or even to trade with others but they don't need "diversity". Diversity is really just putting the "cart before the horse" in regards to tolerance -- people assume that since tolerance has personal and economic value, circumstances that require tolerance (diversity) must be inherently good. The fact that diversity has become its own end goal in the socially imploding west (at least in regards to most of western Europe), often with horrible results, speaks to the fact that creating a situation in which extreme tolerance is necessary was not a good idea. Tolerance can be a reaction to things we can't change and a way to better ourselves but to confuse a treatment with the absence of a problem is a mistake. We aren't tolerant because needing to be tolerant has inherent value, we're tolerant because it's a way of coping with things that we can't fix and ameliorating not just the hubris of other people but also our own hubris.
Tolerance then is a reaction to diversity, and often a positive one but a person shouldn't get into the habit of hurting themselves because they enjoy the cure. There will always be people who say "I am tolerant, I like everyone except those who disagree with me" while living in a bubble of their own creation, then going around trying to burst other people's bubbles because it amuses them (and makes them confident in the strength of their own bubble) but panicking if someone tries to do it back at them. It is probably better to avoid, as the saying goes, sinking to their level.
I think it is also worth mentioning that since everyone has fundamentally unique aspects to themselves, the society in which tolerance is not needed because everyone in the same is fundamentally unattainable. This is another reason to promote the "cure" of tolerance without also promoting the "disease" of diversity. A person ultimately needs to find harmless surrogate or recreational activities that don't involve going after other people, or creating problems in an endless loop of "deliberately created problem + self-fulfilling prophecy as cure = more problem" just because it distracts you from seeing your own flaws and justifies your hunger to seek power over others.
One thing that art does is it can encourage a lack of diversity (through the promulgation of culture) without necessarily attacking others. In doing so the "cure" of tolerance becomes less necessary but not due to hostile action. It also gives people who may not have an immediate survival goal something that they can focus upon. Unfortunately, many hostile people who generate "cognitive dissonance loops" as I described earlier are failed artists. I personally believe that an artist doesn't fail because they are "bad" but because they actually failed to reject their own hunger for power over others. Real art can be a social experience. If they had more patience (or a greater capacity for tolerance) then art for art's sake (and not the kind that disparages people of other viewpoints) would have been good enough for them. It might be said that the end goal of both the artist and the martial ideologue are the same and the difference is only in their capacities for forms of aggression vs. their capacity for real tolerance.