A visa is no guarantee of entry into the US (or other countries) in the first place, let alone something guaranteed to never, ever be revoked.
A country can allow, or disallow, entry by an alien at any time. A country can revoke permission for an alien to stay in that country at any time. The only entity it is responsible for answering to is its own laws and procedures (which the country may change at its discretion), and not the wishes/demands/pleas of said alien.
alt Hacker News
A visa is no guarantee of entry into the US (or other countries) in the first place, let alone something guaranteed to never, ever be revoked.
A country can allow, or disallow, entry by an alien at any time. A country can revoke permission for an alien to stay in that country at any time. The only entity it is responsible for answering to is its own laws and procedures (which the country may change at its discretion), and not the wishes/demands/pleas of said alien.