Bullying typically goes in a vicious cycle in families. Kids learn it from parents, and so on, and so on, world without end.
Not always, but often.
Bullies come in all shapes, sizes, ages, colours, religions, ages, and ethnicities.
Bullying isn't something kids necessarily "grow out of". It should always be deemed unacceptable and behaviour should be redirected as per age.
If not, it grows, and grows, and grows, and you end up with Trump and Vance.