I would suggest that the strikes are targeted to hit the most people possible, thus having a bigger impact, which is basically the very reason for striking. If you believe they're specifically aiming it at 'poor' people, I'm afraid I think you're utterly wrong.
You say 'they', but who do you mean? Certain roles are reasonably paid, but by no means all. As you say, you can't fault them for fighting....yet you seem to contradict that with the last part of your comment.
The 'poor' include the union members, and it's the job of the union to protect it's members interests. I guess you've never needed
such protection - good for you.