>Looking at it from Europe - it is such a weird inhumane practice.

Pretty standard practice in many technology(not just IT) and finance companies in Europe as well.

>If you don't trust your people so much, why to hire them in a first place?

It's not about trust, it's about risk, and most companies operate on liability and risk mitigation. If society ran on trust alone, we wouldn't need contracts, door locks, passwords, IDs, judges, security cameras, jails, police, etc.

You can verify someone's performance at the job interview, you can't verify their trustworthiness, especially once they've learned they lost their job, even trustworthy people react irrational once emotions hit making snap decisions they'll later regret without thinking of the consequences on the spot, and you see innocent people suddenly turn vengeful or violent and break the law (just look at relationship breakups and domestic violence).

You can't predict such reactions, so best to prevent them instead of chasing damages from them later through the court system.

Put yourself in a business owner's position for a minute. Nobody wants to be the "this former employee set my building on fire after I gave his notice, by leaving him in the flammable material warehouse unsupervised, because I wanted to show him that despite the layoff I still trust him".

For some businesses and jobs the trust alone is enough, for other jobs that involve access to sensitive data or money, it's straight to paid garden leave because nobody wants to risk it.

>Then you have extra 3-6 months of work to pass your knowledge, train replacement and document everything.

Yeah, that happens sometimes like for CxO's, managers, execs who get generous golden parachutes/severance packages, but for rank and file workers in the trenches, having to show up to a workplace you know you'll soon loose, for several more months of work till it's finally over, feels like torture unless you're getting a crazy severance package. That's like your wife telling you "honey, I'm divorcing you, but I still want you to live with me for 3-6 more months, and perform your regular duties".