The person you're responding to is trying to establish a distinction between fares and taxes. They're saying that the public infrastructure drives economic growth, and posits that the growth in tax base from these projects should be enough to cover fares.

Whereas you see all government revenue as going into a single fungible bucket, and some people with your view may believe that recovering $700M of additional fare revenue is both practicable and necessary.

It's really more of a question of "who pays", in my opinion. I personally think any revenue system with low overhead is a good one.