We go school (we go to the schoo)why don't we use' the' here

If you say something as it is primary purpose.. You should not use "the" before public places. If you express secondary purpose, you can use "the" Ex : He goes to school regularly. (to study_ primary) Yesterday He went to the school to meet his friend. (not to study, to meet his friend_ secondary)

If we use "the" here.It means not any school.It is a particular school which we are talking about here.