Probably that groups discriminated against often discriminate internally. Recurse a couple times. Rarely is someone only discriminating or discriminated against. Most people are both.

It's self similar on different scales. On a small scale there's small discrimination. On a large scale there's larger discrimination.

Maybe causing fractures in the group?

Maybe, "self-perpetuating".

Very coarse racial/religios groups, (caucasians/asians/africans or christians/jews/muslims) discriminate against each other. But those groups are each divisible into smaller groups, which discriminate against each other just as hard, and those groups are also divisible into yet smaller groups, which discriminate against each other just as hard.

There's a famous old joke about this problem, which goes as follows. Once I saw this guy on a bridge about to jump. I said, "Don't do it!" He said, "Nobody loves me." I said, "God loves you. Do you believe in God?"

He said, "Yes." I said, "Are you a Christian or a Jew?" He said, "A Christian." I said, "Me, too! Protestant or Catholic?" He said, "Protestant." I said, "Me, too! What franchise?" He said, "Baptist." I said, "Me, too! Northern Baptist or Southern Baptist?" He said, "Northern Baptist." I said, "Me, too! Northern Conservative Baptist or Northern Liberal Baptist?"

He said, "Northern Conservative Baptist." I said, "Me, too! Northern Conservative Baptist Great Lakes Region, or Northern Conservative Baptist Eastern Region?" He said, "Northern Conservative Baptist Great Lakes Region." I said, "Me, too! Northern Conservative Baptist Great Lakes Region Council of 1879, or Northern Conservative Baptist Great Lakes Region Council of 1912?" He said, "Northern Conservative Baptist Great Lakes Region Council of 1912." I said, "Die, heretic!" And I pushed him over.

At least credit the man who said it: Emo Phillips

I didn't know the author, edited, thanks!

Think of the fractal images, when you zoom in, you see more fractals (discrimination). Discrimination happens even within sub groups that are being discriminated against. It is rarely one-way.

A common example is women discriminating against women co-workers by gossiping and backstabbing them in the social aspect of the workplace. We may not see that it is discrimination (on the basis of gender) because it's women doing their thing.

In the Deaf community, we experience discrimination every day from those who are hearing. Then there is a big one against people who identify as "D" deaf [those who identify with the Deaf community as an identity] and those who identify as "d" deaf [those who identify as having an impairment]. Those within the deaf community additionally discriminate those who aren't "deaf" enough, and then in turn, even discriminate against deaf who are mentally handicapped.