As the more measured, mature posters have outlined, it's very, very unfortunate that exclusion is often the only way that spurs the LEA into action; it actually usually takes 2 permanent exclusions to get 'specialist' provision. And for a primary dc that's a lot of 'shit' to recover from, particulary if they have a SEND condition and their behaviour (around the age of 7 as they're still young and can't express themselves in calm ways yet, still forming) which isn't due to some environmental factors such as poor parenting, DV, substance abuse, etc., which can also produce violent and aggressive behavior.And the latter situations can also produce the quiet, withdrawn and/or amenable child.
However, being the parent of an excluded autistic dc, I don't think that teachers should put up with aggressiveness from pupils, neither verbal or physical, at all. I know I don't.
I may have withstood, as a parent, some violent reactions from my small child which I was able to contain but mainstream teachers shouldn't have to; only appropriately trained people with the right mindset and skills to do so can.
Having said that, I've seen an increase in bad behaviour in teenagers and children and they're getting younger when they start this too and this trend does need more focus.
My ds is fine, the violent phase was shortlived and he outshines the many 'gobby', disrespectful, violent young people now with his calmness. I'm a bit of a burnt out case but will be happily waving him off to uni in sept.