Exclusion: Who benefits?

There is two types of exclusion, a fixed period and a permanent exclusion.
A fixed period exclusion refers to the pupil being moved away or suspended from the school for up to 45 school days in 1 school year. In this category of exclusion, I also think of a medical form of exclusion. This can for example be pupils who suffer from the characteristics of ADHD, who is being drugged with retalin to be kept quiet.
Permanent exclusion refers to the pupil being expelled. The pupil will hereby be the local councils responsibility. The council must therefore arrange a full time education from the 6th school day.

If it is normal to be different, why do we then exclude?
We could blame the child for being different, blame the parents for not taking care of the child, blame the child's neighbourhood or even the school.
But is it just that simple, that we can blame us out of troubles? One thing is for sure, when excluding, we are giving up. And whether we like it or not, we are blaming the child by removing it from the classroom or the school. If we already are excluding individuals in this early stage, how do we ever secure the person will take part of the society in a later stage?
For me it does not make sense, to decrease low achieving pupils chances by excluding.
I think it is narrow minded, to see “blame” as a solution for including children. Lets take a look at who is most frequent to be excluded. The most likely categories is: Boys, Special Educational Needs, children receiving free school meals, children with disabilities and black and dual heritage children.
If we by excluding try to fix the matters of diversity, I think we are raising our children into believing it is ok to avoid differences later on in life. We all do agree, that if you are having a birthday party, it is not ok to exclude certain persons from your social circle, just because they are different. But how come it is accepted in a classroom or school situation? 
I think our true values and beliefs need to reflect our actions. Therefor I see the responsibility for going against exclusion, as an responsibility for every person in society. Problems will never disappear by excluding them, but will more likely bloom in a nearby future.