I couldn’t agree more.
Unions are criminal organizations for the propose of extortion and thief. By all rights they should be in jail.
But your also right in a free country they could exist if there was a true monopoly and an no willing workforce.
After all an employee can’t fire an employee unless that employer can find someone else willing & able to do the same job under the same terms.
On the other hand, an employee won't stay in the union for long if this disqualifies him from all jobs. It may be my right to wear a KKK robe and go to interviews (I don't really know if it is legal or not) but it would be mighty stupid and won't land me any jobs.
If I am the business owner and my policy is not to hire union goons I simply will hire contractors or outsource the job to someone who does it right. The golden rule is in effect ("He who has gold sets the rules.")
The "same terms" is not a required condition. Often same terms are no longer available. Can you buy a gallon of milk for 10 cents? I guess that was the price 100 years ago. But those "same terms" are long gone. Every new day brings new problems. If the local labor becomes too expensive you look for other labor. Giving in is not an option for a small business because too much is personally invested. A large company, full of managers who personally don't care one way or another, can collectively sell its soul to the Devil, as long as it is "convenient" at the moment.
Then why should we be surprised if thousands of business managers escaped the union-ridden, red-tape-entangled, drowning in taxes USA altogether? There are plenty of countries in the world where you can open up a shop and not be looked at as an enemy of the people; where every worker has a right and responsibility to sell (or not to sell) his labor at the personally negotiated rate, and enter and leave this contract as mutually agreed.