We are separated by not just a language, but the ideas behind it!
Precisely how does a strike "protect the job"? How does a person who walks across a picket line "interfere with a strike"? Do Europeans use words like this to hide the socialist leanings of your government and your people, or to justify them?
A strike is a power play by a group of workers who bet that they can force their employer to cave in and meet their demands. Many strikes have been called to force unreasonable demands, and many have been for good reason. An employer ignores demands in his power play to get away with as much as he can. May the ones with the most power win!
Without unions, employers would put workers into cans and sell them to make money. With unions running the whole show, nothing would get done and everybody would sit around and play cards and draw checks. With a balance, the world works. The US labor laws are finely tuned. Workers who replace strikers are allowed, sometimes, and when they are, their jobs are not secure.