When you have reached epidemic levels of a negative thing, fighting the epidemic from within is futile. You need to create a counter-epidemic that takes over. An epidemic of nastiness can’t be won by explaining to people how bad being nasty is, the merits of not being nasty or the penalties on offer if nastiness continues.
An epidemic of nastiness needs a counter-epidemic of kindness, where all energy is directed towards injecting kindness, not towards getting rid of nastiness. I use this example because it’s easy to imagine what the effect would look like. The principle applies to any other situation in the organization or the macro social world.
If you want to change something that is not working, and the issue has become widespread, try to find something that is the opposite and see how you can inject it and scale up. This is more powerful that trying to fix what doesn’t work.
In behavioural terms, this makes sense, but still it remains somehow counterintuitive outside this perspective. I have explained this in my book Homo Imitans. 
We spend 90% of our time fixing problems and 10 % creating new approaches. We need to reverse it: 10% of time fixing, 90% of time creating solutions that will take over and will make the un-fixed problems irrelevant.
‘Fight the epidemic with a counter-epidemic’: if you think this way, you’ll win