Unions are definitely bad for companies, but the fact that companies don't want them doesn't automatically mean that they're good for workers. They're a parasitic drain that's bad for both.

Also, with the sole exception of Japanese bus drivers, every union I know of that's ever gone on strike has, in doing so, used innocent third parties as collateral damage.

Are the unions once damaging people or is it the companies that do not have sufficient contingencies when their employers take collective action? I don't think it is unreasonable to expect them to take account potential issues with their employees. After all it is a free market and they could source services from somewhere else during these times.

You can claim they're a drain on both all you want, but you're just stating an unsubstantiated opinion that flies in the face of reason. Why would anybody join (and stay in) a union if they're unequivocally bad for everyone?

Are strikers holding people hostage? Or are they just refusing to do their jobs?

If Walmart closes its union store, which it has done, how is that not bad for everyone?

That's not unions being bad, that's Walmart being bad.