That is the nearest to an explanation in all the answers ie saying "Beer is NOT free' all the others still confuse me as I read its literally. and 'Free as in b

That is the nearest to an explanation in all the answers ie saying "Beer is NOT free' all the others still confuse me as I read its literally. and 'Free as in beer' makes no sense so the whole thing just does not compute. I do understand what GPL does and the reasons for this just not this slogan.