As per this blog, it should be possible to set Organization in JSM using reporters email domain:
https://blog.codebarrel.io/set-organization-in-jira-service-desk-using-reporters-email-domain-e705be9d4717

However, it doesn't always strip the domain. For example, Icelandic websites apples.is should become Apples. Rather, it remains as apples.is

Suggestion

Setting organization using reporters domain should support domains other than .com