it is intended to be used only to mark abuse

Abuse, a currently fuzzy concept open to wide interpretation. My point remains, anyone can flag anything. That's how the system works.

Disagreements happen, and ... discussion is more appropriate when it does

That's your opinion. But that's not a design principle for the system.

Flagging , however, injures the other party in that it damages reputation

There is no injury. This is hyperbole again. And it only reduces your reputation when done by a user with a higher rep than you, which is, by the current design of the system, that user's right to do. You have no right to any particular reputation number.

[Flagging] potentially affects earnings

Of course it does, because the system was designed for it to have that power.

It is one user forcing their will upon another

There is no force involved.

We don't want Steemit to be a place where users inflict harm upon one another through their unconscious actions

This is a load of horseshit. You got flagged. Get over it and try again. Not everything is a political movement.