I understand 8chan is like 4chan but with less regulation and more controversy... Why is it registered or operated from the US, instead of, say a company in Tuvalu that rents servers from a company in Pakistan, but the encryption keys are with the company that manages the servers, from South Sudan?
Because of the US free speech laws. The US is the location where the rest of the world usually hosts there problematic content. It is, or was, also rampant with non nude child pornography sites. While illegal in most of Europe (and other countries I assume), the situation in the US seems to be very different. The whole thing came up in Germany when the government used the numbers of chiid pornography sites they couldnt take down to push for a censored internet. Most of those sites were hosted in the US.
If you host your stuff in Sudan or Tuvalu or Pakistan, you simply get removed on the first report. Why should they continue to host you? The same thing happened a while back with a Ukrainian or Russian ISP provider who didnt react to reports, the whole ISP was simply dismantled. Only because the cooperation between the countries governments isnt optimal doesnt mean the local countries will turn a blind eye to abuses from their servers.
The owner is based in the Philippines who also owns one of the largest Japanese imageboards and some of the hosting infrastructure. Not to be confused with Frederick 'Hotwheels' Brennan who used to run it subsequently quit and moved back to the US after selling his interest.