> The average bachelor graduate will demand higher wages than the average high-school graduate.
In economics the word 'demand' does not mean 'demanding' your wage or 'demanding' a certain price. Economics demand is how many people want something at a certain price. Lets repeat that. 'Demand'... is how many people... want something ...at a certain price.
It's not at all related to literally "demanding higher or lower wages", or "demanding higher or lower prices" as you are suggesting -- that is the colloquial definition of demand, and IMO it really should not be used when talking about economics. They can't be substituted for each other.