Because most people wouldn't bother taking it to court.
If they rolled over and paid up every time their chatbot made a mistake, that gets expensive, and teaches customers that they can easily be compensated if the chatbot screws up.
If they fight it tooth and nail and drag it all the way to court, it teaches customers that pursuing minor mistakes is personally painful and probably not worth it.
Scorched-earth defense tactics can be effective at deterring anyone from seeking redress.
It's the same fundamental reason why customer support is so hard to reach for many companies - if you make it painful enough maybe the customer will just not bother. A valuable tactic if your company imagines customers as annoying fleshy cash dispensers that talk too much. Having flown many times with Air Canada I can confirm that they do seem to perceive their passengers as annoying cash dispensers.
Wait, couldn't they have tried to settle as soon as they realized it was actually going to court? I thought that was the modus operandi in the US... is it not a thing in Canada?
The point is quite literally to make you give up trying to contact customer service and just pay them money, while getting their legal obligations as close to a heads-I-win, tails-you-lose situation as possible. That's not the mysterious part. The mysterious part is, why did they even let this drag into court for such a small sum?!