One way is to decrease the granularity possible, so a finger can easily pick the “exact spot”. Basically make movement discrete (maybe not the animation, but the locations you can be at from a game logic perspective).
Ok but you're losing complexity, and still need accuracy in that case. I think your suggestion would work for a turn-based game, I just don't think mobile is a good media for RTS.
I don't think the poster was suggesting porting Starcraft to a touchscreen. It's a design challenge to figure out what changes need to be made to accommodate the genre for touchscreens. It's not obvious because people haven't put in the work yet.
It was a also a design challenge to make the genre work in the first place for mouse and keyboard.
I would argue you cannot port any RTS game, not just Starcraft. Mouse and keyboard are not a constraint, they are excellent for RTS, which is why the genre is also not so strong in consoles.
And none of us are saying anything about "porting" we are talking about adapting the medium to a new format, but you seem convinced the only way to see it is exactly how it was designed in the 90s.