The union also fights against CDL requirements for better/safer drivers and allows excessive overtime because it pays out so much.
Its not a good union by certain measures, like a lot of big unions focused on low/no skill labor it can help raise salaries (and raise product cost) but also not be helpful in anything they think 'hurts' workers like mandatory unpaid breaks, CDL requirements, background/credit checks, etc.
Modern unions have little in common with the unions of old that existed before we had any real safety regulations and far less labor regulation. Now they exist almost solely to return as much financial value as possible (wages) for the investment (dues).