Authors should support other authors. That's what I do. That's what I think other authors should do. That's what a lot of other authors do.
But I know a stinky small minded "author" who needs to be slapped upside her weasel head for being rude to another author for no good reason. Another writer's success does not diminish our success.
Jealousy is an ugly thing, and it will NEVER lead to success in any form or fashion.