Why is stereotyping bad and who is to blame for it?

Question

I have often seen the cry of stereotyping linked to "racisim".
I wonder why, exactly.
If a school has a failure rate of 55% it would be natural to call it a bad school and schools are often un accreditied because of this. Is that not a type of stereotyping? After all, 45% did not fail!
The same thing is true of ANY identifiable, social group!
Stereotypes are born of the actions/attitudes/beliefs/practices of a LARGE percentage of that identifiable group.
Is not that subset of the larger group to blame for the growth of said stereotype?
Let us take one that bothers very few people, namely politicians.
Are they ALL croocks? Do they ALL take kickbacks and bribes, or show favoritism for large contributors?
I cannot fathom that EVERY SINGLE ONE does.
But the STEREOTYPE is one that tells the general population, that this is a truism, and that politicians are neither to be trusted nor believed
Who holds more blame for this view?
The ones who ARE what the stereotype acurately represents.

Please understand, that I am NOT trying to excuse prejudice. But I would like to see, for example, the black community 'take care of its own' by no longer accepting lower school performance, gang membership, unwed mothers, welfare recipients, drug dealers, etc in comparison to other groups.
Same with "Latinos". They should be the FIRST group enraged about the huge number of Illegal immigrants, gang members, drug dealers, illigitimate children, born to married men from other countries, etc.
Of course, I WILL be called RACIST because I used these two groups specifically.
I did so because these ARE the stereotypes, again, orn of the actions of members of these two groups.
Why do I not say Japanese on welfare? Even though there are, certainly, some on welfare, it is NOT the stereotype of THAT group and would NOT serve as a good example!
No one thinks "lazyJapanese welfare rats!"
Do they?
No segment of that group made this stereotype-able!
Intelligent opinions?

Answer 1

Stereotypes are always nice to look at. best example:cheerleaders in high school. those people crack me up. a stereotypical view is just bad if you generalise everyone

Answer 2

stereotypes are bad when refering to ethnicity

but some stereotypes are just about social groups in school

Answer 3

Get off the cross, somebody needs the wood!!!!