I read the 3 arguments and fail to see how they argue for it being stupid?

Yes, the price will increase, yes, some scab might accept the low bid, yes, it might in breach of their bullshit contracts.

It's true. All of it. And it's still the right thing to do, because these are not arguments for not doing it. The 3 points only describe what the drivers are doing. It does not explain why they shouldn't do it.