[foobarchu]

I'd say the difference is that Whitehouse.com is granting it on an individual basis, as a whitelist. On Twitter, Trump is himself picking and choosing who to blacklist. It's ok to only allow some people to join the conversation, it's not ok to selectively say "no, you CANT join" due to personal disagreements.

Juvenile comparison, but it's like how school teachers won't usually let kids give out birthday invites in class unless they give one to everybody, because otherwise you get just the unpopular kids being selectively disinvited. Yet those kids are allowed to give those invites outside the classroom/public forum