AC pricing

Take a look at this pricing list from Air Canada. Routing is from HKG
to BOS. What's wrong with it? A faulty system or the airline is
employing a new tactic making people to pay more because Business
Class looks cheaper thereby boosting the airline's bottom line?
Ridiculous! How the heck can you have Tango fare more expensive than
the lowest Business Class fare? BTW the prices are in HKD.