If something is not to your taste, but is actually broadly acceptable, then you can find another school.
Like I said upthread, this school is not trying to establish a cult, but a culture of learning.
Look at all the top schools and the types of stuff people say about them. 'Culture of discipline, learning, teamwork, values, pride in their school'. Now at the top schools, kids will often turn up already with those cultures embedded - from their families, from team sports, from places like Beavers. And private schools also cultivate them - school uniforms, school mottos, cheering on teams in competitions, successful ex-pupils coming back to give motivational speeches.
Other schools do not necessarily have an full intake where hard work is valued, good behaviour automatic, skills of co-operative working with others embedded. They don't necessarily take pride in their school, and the message from others may also be negative. For a school to be successful, that culture of hard work, discipline and positive values needs to be deliberately established and embedded in a more overt way. Not all pupils will need it, and those parents are likely to be the ones rolling their eyes, but for the school as a whole to work effectively, the message needs to be consistent and constant.
I would imagine that most of us are constantly telling our children to work hard and be kind to others, by what we say to them, the activities we choose for them and the interactions that we model for them. Is that brainwashing? Probably. But with good intentions.