IQ is not bullshit at all. It is the best way we have to make a generalization of our capabilities. Lower IQ is even associated with lower impulse control and violence. Very high IQ is also associated with certain negative traits.

A person who scores 80 on an IQ test will NEVER be able to take a doctors degree. A person with 60 IQ will never be able to do manual labour without proper supervision.

IQ is probably the single most important tool we could use to improve everyone's lives. But it is so personal and "cold". It's so much shame connected to it, because it basically says; "You have an IQ of 80 and you can't become this and this and that" But rationally speaking it would be better for that person if he would accept that. My IQ is somewhere between 115-120. Which means I shouldn't go for certain things. I wouldn't be a great engineer. I probably couldn't get through a phd in maths or physics. My IQ has many limitations. I'm not incredibly bright. I'm a about a standard deviation above average. I understand some things, but there are tons of smarter people than me who look at me like a simpleton. And someone with an IQ of 80 is a simpleton to me. And someone with an IQ of 50 is a simpleton to them.

What's there to be so scared of?

Research on IQ is very well documented. But because of "hurt feelings" on behalf of others no one really pays any attention to it. It's a big mistake in my opinion.