Yes. There is never a situation in which unionization is “unreasonable”. To say otherwise is to allow businesses to have near unchecked leverage over their workers.
Your tone is respectful but your questions don't really make any sense to me. The company and the government hold unions responsible, they are not all-powerful and often much less powerful than the company. No, it is not justifiable to deprive you of your rights, and fortunately unions can't do that.
They are powerful but not unaccountable. Every time a union strikes they use up some of their power, both with the general public and their members (who want to work!).
In the case of many public unions they are legislatively prevented from striking.
The idea that unions are the ones with significant leverage over their employers in this day and age is baffling. Just look at the railroad workers who got manhandled by a Democratic government!
If there are not enough jobs in the area and not enough capital to kickstart businesses, the people in that area are in a situation where something is better than nothing. So a corporation can come in, offer below subsistence wages and the people will feel as if they have no other option. It's not what the labor is technically worth because the value produced by the labor far exceeds the wage given to the laborer.
Individual laborers have no power to fix this. The employer can fire them and exploit the next desperate person. They can even cycle through back to the original person as they get more desperate.
Collectively, the laborers can do something. They can redress the balance between laborer and owner. But only as a collective. The minute the individuals are allowed to operate independently, the old system reasserts itself.
Stop carrying water for people who won't even allow you a drink for your efforts.
They aren't "a part of" schools and corporations, they are the schools and corporations. It is obvious why 90% of an organization can make a decision to shut it down. When unions are smaller and don't constitute such a large portion of an organization, as will be the case with Tesla, they are not able to shut it down.
With all due respect, I'm at a loss of words, so please excuse the term: You appear to be thoroughly brainwashed. A worker's union protects you, as an employee, from overreaching corporations. It is held accountable by laws. They don't deprive you of your rights, but holds corporations accountable for doing so.
A union does not protect you by default. In fact, their actions might endanger you if it runs counter to the continuation of the company's mission. And companies are already held accountable by law, so you do not need a union to do that, either.
What a union actually is? A competing power structure within a company, and op questions whether such a thing is reasonable in this case. You did not answer but instead tried to try to brainwash op by shaming them into accepting your essentialization of unions as something good in all cases.
Holding companies accountable via the law does not work, because there is a fundamental imbalance: People compete for good jobs, so they are willing to accept a certain amount of injustice, which gets larger the fewer jobs there are. Employers know this, and use it against you: You can't do anything against it on your own, because they will simply hire someone else.
Unions in turn fight this by representing a lot of employees, so the employer cannot simply ignore them. The have fought bitterly for humane conditions, a 40 hour work week, and abolished child labor. You might call this overly dramatic, but that's where you get if you let corporations run free (remember those news stories about child labor in Texas lately?).
A "company's mission" doesn't mean shit if it doesn't even treat its employees like human beings. If you want to be a good slave, have it your way - but stop characterising unions as somehow evil.
By creating an environment of respect in employment terms. In a word, inertia. There is a reason employment contracts with greater than 40 hours a week are almost unheard of. Union blood was spilled to bring it down to that.
It's unreasonable, (and depending on the jurisdiction, illegal), for corporations to make a difference between unionised and un-unionised workers. So by promoting improvements for their members, they promote improvements for all employees.
Why is it unreasonable? There are plenty of auto manufacturers in right to work states who do just that. Why shouldn't anyone be allowed to work for Tesla in Buffalo regardless if they want to be a part of a union or not?