Why love is blind?
Because some people were willing to turn a blind eye to their loved one's weaknesses and flaws, which was touching and essential in relationships.
Well, people really should tolerate others' flaws because no one was perfect.
But in Hydra's curse, the one who really lost their eyesight couldn't see the danger in their relationships, and couldn't see anything happening around them at all.
The people with this symptom didn't get killed like others, but because of this, they couldn't continue to attack Hydra.
When they insisted, they even mistakenly attacked their own people rather than attacking Hydra.
There were people who got blind..and of course, there were people with lower IQs.
It was a common saying that people in love usually became a bit stupider than their usual selves, and Hydra's curse just exaggerated this part.