The point is that, if you choose to have your child's education provided in a state school, you have to 'sign up' fully to all that entails. Equally, if you choose to opt out completely and Home ed, you sign up fully to all that entails - total responsibility for all of your child's education.
Having done both, the education provided in each way is simply different. You can't compare it using a 'time spent' model.
From my current 'teacher' perspective, the point is that education in state school is a collective process. Certain rules are made for the 'whole group', because to do otherwise, even though it prejudices some individuals only a very tiny amount, prejudices the education of the whole group a lot.
If a HE child goes abroad in June, for one thing that is likely to be with one of their primary educators, and so there need be no break in the education, and even if it is simply a fortnight in the sun, no-one else's education is in the least affected. the child and family can simply pick up where they left off on their return [HE people, I do know it's not really like that, especially for more autonomous HE. But I'm trying to keep iot as 'school like' as possible a model of HE, for simplicity].
In a school situation, in that scenario, the remainder of the group has moved on. The education of the remainder of the group is affected, because either the teacher has to repeat teaching that the rest of the class doesn't need, or devote individual time to the pupil who has been away, to the disbenefit of the remainder of the class, either immediately after the holiday or each time a topic that has been missed is touched upon. Of course the same happens when a child spends 2 weeks away ill, but that is unavoidable. If every child takes 2 weeks' holiday per year - much more than is ever taken on average by illness - then there is virtually no point at which the teacher is genuinely moving all children on without the 'brakes being put on' by children who have been away for key teaching.