Here it is:
I DO think that 7-9 results in Go Aggro are not a 'hit', per se, if you're looking at it like 'A hit is me getting at least part of what I want'. But I think that they aren't meant to be. I think that 7-9 hits on Go Aggro are non-resolution outcomes leading to untenable situations, which players will then use Moves to try to resolve. In other words, Moves Snowball.
The NPC can offer something he thinks you want, like a cupcake, sure. But it's still your decision and you say, 'Fuck your cupcake and you' and you shoot him, with the MC deciding that that means Seizing By Force, so we roll for that and play to find out what happens.
It's a partial-resolution, which to me, is the heart of Moves Snowball.
My gang is Going Aggro on Jackson's gang. I 7-9 and they barricade themselves in. It's not a cave, or a suck it up and it's not a miss. I don't get what I want, they barricade themselves in and now we have this fucked up situation where my gang and I are trying to get in. And we'll probably use moves to try to do so.
An interesting point towards Go Aggro 7-9s being a hit or a miss:
In play, in the back and forth, a 7-9 Go Aggro hit means the rolling player says something, then the character being acted on says something still in the same move, from a list. Like 'yeah, I barricade me and my gang in. We're putting boards up in the windows, taking potshots out of the windows, putting shit in front of the doors, all that'. He says all this IN THE SAME MOVE THAT THE OTHER GUY ROLLED. Some one else's Go Aggro.
So then there's this natural thing where in the back and forth, it goes back to the other player, the orginal one who went Aggro, because it feels like the guy being Go Aggro'ed on just went, because he talked.
So a 7-9 Go Aggro may not be a hit, in that you get what you want. But it means that you do something and then they do something off a list in the same move (meaning that they can't act against you in a mechanical way because they can only do the stuff off the list) and then you get the next chance to make a move, like Seizing the house By Force or whatever.
It's an elegent way of making sure a 7-9 Go Aggro doesn't get what you want, but it's not a miss. It's a complication, but not a chance for them to fuck you.