Unfortunately most people in charge of Academies are dickheads. This is why the idiotic rules so many people are describing on these threads have gained such traction.
If you look at the websites of secondary academies, you will see their Headteachers are largely white men in their very early thirties.
Many of them will have been P.E. teachers. I've got nothing against P.E. teachers and I've had plenty of lovely P.E. teacher colleagues. But the type of P.E. teacher who becomes a Headteacher very quickly is the type who has become a teacher because they enjoy power and control. They are also - and I mean no disrespect to P.E. teachers - usually not very academic.
As such, many of these schools are led by blokes who a) are not very bright b) are not very experienced and c) love having power and control over others.
This type of Head loves having nonsensical rules and they love dishing out punishments.
They do not give two shits about education or children.
All they want is an easy audience of people over whom they can wield power. In the world outside of education - in business, for example - they would not have the intellectual capacity to rise to any type of leadership position, and neither would they have the right background or people skills. In education, however, you can quickly and easily move to the top of the chain even if you're not very talented, if you are in the type of school that rewards mediocrity. They know this, which is why they become teachers. They do not become teachers for the children. In fact, I'm convinced many of them don't even like children. They just like punishing them.
Academies love hiring these mediocre mini Hitlers as Heads because Academy chains are largely owned by right wing megalomaniacs looking to make a quick buck out of education and indoctrinate a new generation of children with their right wing views. They want someone who will act as their puppet at the helm of their schools and not have the critical thinking skills to ask questions.
And so here we are, in an educational landscape where teachers are leaving education like rats off a sinking ship because we're forced to work under morons whose motivation is to control rather than educate. And students are forced to sit in rows wearing wool blazers in 30 degree heat, doing lessons from powerpoint slides created by someone in a Head Office 100 miles away, wishing they could be anywhere else and totally disengaged from their education.