How did they convince so many construction workers that unions suck

It really blows my mind that anyone in the construction industry could be anti union. Unions obviously increase your bargaining power and in construction that’s where it’s the most obvious. Union construction workers package is seriously more than double the non union workers in my area. Even the BLS is showing an almost 2 times difference in pay for union vs non union workers in construction. Now I will say usually the states who lean anti union also tend to live in lower cost of living states so it makes sense they would make less but even when adjusted they still have substantially less purchasing power. When did it all change, I read that at one point 84% of the industry was union.