Language & food history time:
The whole aphorism is “A few bad apples ruins the barrel.”

Before refrigeration, apples were stored in root cellars, usually in barrels.

When fruit ripens, it releases ethylene gas.
Those barrels were fairly tight built.
Gas didn’t escape.
1/5

When an apple gets too ripe, it rots.
And because it’s sitting there, releasing gas, touching the apples around it, the apples nearby follow the trend.
It doesn’t take long until the whole barrel is in runaway rotting, because ethylene gas is POWERFUL stuff.
2/5

There’s no way to have mercy for a rotting apple. You can’t fix it; you just have to remove it & the ones around it, take all the others out of the barrel & CLOSELY inspect them. Toss the rotting ones, use the marginal ones now & the rest of that barrel had to be eaten fast.
3/5

So when we say a few bad apples in a, for example, police department, we’re not saying “Most of them are good, it’s fine.” What we’re really saying is “This bad behavior taints EVERYONE around them, and we must react swiftly and ruthlessly if we’re going to save the others.”
4/5

Humans aren’t apples. But organizations form members to its requirements as the members shape the organization to their needs. A precinct that has shown rot must close down for ruthless EXTERNAL examination. Any spot of corruption must go.
Because it’s not OK if some are rotten.