do you think schools let kids pass to different grades on purpose?

I'm sure they do. Schools get paid by the head that the teacher takes account for on their roll sheet. As long as the school is making money--i'm sure they wouldn't mind random kids not getting the quality education they should be receiving.

Unfortunately they do. God forbid that we make them feel inferior because they can't read, write, or do simple math.

You mean without earning the grades ? Sadly, yes---which does them no favors.