It's a failure of hiring, planning, and management. It's an off the books opportunity cost. It's an off the books cost of hiring a replacement. And if over hiring was done willfully, then yes it's straight up unethical.

Irresponsible, careless, negligent. No planning leads to all of this. Ultimately unethical from this point of view

Actually, it is. You have been blinded by capitalism to consider it ethical.

The tribes usually treat the members as a family. While kicking someone from a tribe can happen, it's considered to be a harsh punishment.

In a tribe, when hard times come, people usually redistribute. That's a normal, human way of dealing with that situation. Not a layoff.

The other aspect is the economic crises. When a central bank decides to increase interest rates, it decreases lending to new investments in favor of lower inflation. This can lead to layoffs, instead of having inflation inflicted on everyone (especially the rich with huge savings). So that decision is essentially some random guys get kicked out of economic (and societal) participation in order to prevent more redistribution of existing wealth.

If you think about it, yes layoffs are deeply immoral. But we can understand, why they happen in capitalism, as a sort of big tragedy of the commons.

It's an unpriced negative externality.

It is unethical, if there was nothing wrong with their performance and the company never tried to find a replacement position within the company. Stop licking boots, I heard they don’t even taste that good.

When done for profit maximizing reasons it's not any worse than capitalism itself, but then this degrades into whether capitalism is ethical which is off topic