No, it's a time honored practice of negotiation. Just as are lock outs and other ways in which both sides put pressure on the other.
Nuclear missiles and Nuclear armed stealth bombers have been a good negotiating tool also, still doesn't make it a good way to go.
And it is the worker's labor. They strike a deal, a negotiation. An employer will most always pay less than he should if he can get away with. And a employee will always want more than he should if he can get away with. It is better for both if they negotiate in good faith, and be less adversarial and more as partners. They need each other.
It is only the "worker's labor" if the company feels like paying the worker for that labor, otherwise, it's the workers time in the unemployment line and the person that accepts what is offered by the company has a job.
A company never pays less than it "should". It should only have to pay the amount necessary to get and keep a quality worker, and only to quality workers, based upon skill level needed, skill availability in the labor market, training required to attain the needed skill and the economic needs/desires of the company.
Labor is a competitive market. Each person is their own product they are trying to sell. The company, just like individuals do, shops for the best deal available for their needs/wants. If worker A is too expensive, then they hire worker applicant b, etc. If the price for worker applicant B is acceptable but quality of the applicant, then they move on to worker applicant C. Just like a company has to balance the cost and the quality of it's products to compete in a market, a potential worker also has to do so. It is incumbent upon the individual applying and seeking employment to meet the requirements to be employed, they company does not have change it's requirements unless it is unable to meet it's needs.
Unions are like a third party stepping in as saying that all products must have a minimum price to be purchased. How would you like it someone made it so that all food items must cost $5 minimum, regardless of quality? Wouldn't work for a product, doesn't work for labor because labor IS a product being marketed.
Frankly, companies should be able to fire striking workers. They were hired to do a job, they are not doing it, so fire them and hire someone else. Besides making labor cost more, Unions and a lot of Labor protection laws force companies into retaining extra, costly and non/low productive labor.
And all of those costs are passed on to consumers. In the end, a Union forces higher labor costs in one segment thus raising the cost of product A, workers needing or wanting to by product A must now make more money to afford that product, so the workers that make product B and C now want a raise also, so they force an increase in their labor cost, thus raising the cost for products B and C. Since the labor producing product A wanted the raise to afford more or better products B and C, even though they got the raise, they still cannot afford more or better products B and C because those laborers also got a raise. And so the cycle begins again, except for labor producing product X who was satisfied with their pay and benefits but products A, B and C now cost them more. Eventually, those producing product X will also have to have a raise or they cannot purchase the desired/needed levels of products A, B and C. If products A, B and C are necessities and product X is a luxury, eventually, product X will disappear because it is no longer affordable to the laborers making products A, B and C and the workers producing it now become unemployed.
How is this constant cycle of inflation good?