No, it’s an English term. See for example https://www.merriam-webster.com/dictionary/fair

It's kind of socialist because some of the socialists want to make that decision societally. That we as a society should make all companies have the same norms for when to fire staff.

Because it's a topic for them in a way that it isn't for other political groups, the term is sort of socialist. At least within politics. HR departments probably also talk about fairness ;)

So if you accept a job, you can trust that the next CEO won't change your relationship to your employer wrt. firing. But the next government might, after the election.

Semirelated anecdote: Where I live, one of the big employers is well known for its particular culture: No layoffs since 1961 and a certain solidarity. The recruiters mention that to prospective employees. Some other companies are said to pay better.