Is it fair for profitable companies to fire staff to make more money?

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.

The first part is free, but then you have to pay to be able to read the full thing.