That's how you end up with pay by seniority rather than performance

Frankly this is the fault of the employer not the union.

Yes the union is the one _forcing_ the employer to enact such policies but _why_ does the union exist? Because the employer treated their employees unfairly.

Unions are a bandage on a gaping wound, yes you can say the bandage isn't doing the best job. But why do you have the gaping wound to start with?