The fog caused the humans to lose their advantage in visibility.
In a large-scale battlefield, visibility is particularly important.
If both sides have similar technology levels and can accurately locate each other, then space warfare would be a typical war of attrition.
The competition lies in the production capacity and respective population sizes- whoever can withstand more, wins.
However, when one side acquires technologies such as invisibility or fog-like concealment, they gain a visibility advantage.
When the advantageous side knows the location and movement direction of the disadvantaged side's military strength, they can either arrange long-range, large-caliber pre-aiming, make on-the-spot decisions and quickly concentrate their advantage to eliminate the enemy, purposefully leave an area open to lure the enemy to make a futile move, open a gap from another side, or arrange a lot of explosive devices or disruptors in the enemy's target area in advance.
