Ask HN: Why US tech companies asking for work permits from remote freelancers?

I don't think you need it if you're working remote. We at HackerBay.io never ask for permits / visa if you're remote.

One factor for why companies are more comfortable hiring a person living in US is that then both ends of the contract fall under US law. Meanwhile, if the freelancer lives overseas, then the combination of US and that country's laws are applicable, which can create an unparseable mess. This is especially important in area of copyright, because the company wants to be 100% sure that the freelancer passed the rights to code to them (and you can't be 100% sure of that if you don't understand applicable laws of the freelancer's country). You could even potentially lose a VC deal because of it, as unclear status of the code ownership could come up in their due diligence.

(I am not a lawyer, this are just my layman speculations).

This question has come up before and I believe the answer depending upon company and whether it was employment or contract.

In my experience, it's flexible. But consider that companies have their own legal departments, advice, and tax requirements that may make the decide on hiring only people in their own jurisdiction. Technically yes they could all hire whoever they want as an independent contractor and make the bank transfer but that's too messy for many of them.

I believe this is for "Remote in USA only" positions. I believe it's due to the bureaucracy of hiring international employees.