Maybe. Unions can become corrupt or politically influenced too. In fact, organized labor is one of the main money makers for organized crime. I'm not saying all unions are bad, just that some can be. Just as any power structure like governments or company management can be too.

I wonder if the major unions have banned together to get that bill introduced and voted on? It could be possible that they wouldn't support legislation like that because more legislative protections can make the union seem less useful.

If the unions don't have incentive to push the bill and more workers are covered by unions and don't see the benefit of the bill because they are already protected, then could that delay or even prevent the passage of those protections? It may end up as a long term fix that leaves non-uninonized groups and groups that seem unlikely to organize, like IT. Of course with widespread existing adoption, a counter point could be less opposition to it.