I used to work with these children in a mainstream secondary. It wasn't the children with special needs that were the problem, it was the children with behavioural issues.
There is a difference.
Special needs in education is a term reserved for children who have a statement. That is, they have been diagnosed with a particular disorder or syndrome and the LEA acknowledge that they will need extra support.
A child with behavioural problems only, does not have a statement. They just disrupt the class, have little or no respect for teachers, they bully, are not willing to learn etc etc.
Yes you can get children with SN who also have behavioural problems, but I think you'll find that if this is the case, they aren't usually recommended for mainstream education.
The children I had with SN were lovely. Other children were very patient and tolerant with them. Trouble is, that they were always put in the lower classes, where the behavioural problems were. I thought this was very unfair as all they were learning, was how to misbehave.
I won't comment on dp's personal views of children with SN, I'd be wasting my time. But as I have a brother with severe learning difficulties and a nephew with Down's Syndrome, I can only hope that others are more tolerant of these childrens rights to learn in a mainstream environment.