But that's the thing, the IQ says absolutely nothing about ones ethical responsibility or the amount of empathy one has.
It is purely measuring "logical thinking ability". Things like "continue this sequence", "recognize a pattern", etc.
I also often see this dangerous assumption that ones political opponents or everyone with a different opinion than the one which seems most rational to ones own must be "stupid". In reality, the problem is that we focus on something as (arguably) unimportant as the IQ, which measures only something very narrow.
Another misconception about IQ is that those who are more poor or have less favourable job positions must have a lower IQ. To give just one counter example to that, very often, people who have some sort of handicap (ASD, ADHD, etc.) are also "gifted", have a high IQ, are good when it comes to logical thinking. But their handicaps still make their lives more difficult in general, so they face more adversity than someone who is "normal".
Sorry that i wrote a wall of text, was just thinking out loud.
In my personal opinion, the IQ is already a little dangerous, because it assigns a "value" to a human life, but that is an entirely different discussion.