He is not a messenger - that's a person who carries a message from one person to another. He is writing his own message. If he were quoting somebody or posting an article, he could be called a messenger.
Look at his posting history. Every single post is about India, and a third of them have the sentence "We don't want anything to do with India." He also trots out some statements that Indians mock Bangladeshis about believing - things like Bangladeshi muslims all look like Afghans and Turks. These are typically used by Indians to mock Bangladeshis, not claims made by sane Bangladeshis. All the stock lines he uses are caricatures. He is simply trying to get many people to mock B'desh, by making idiotic anti India posts.
That's my judgement. I could be wrong though, maybe he really does believe whatever he writes. In that case, I would prefer to have a discussion with my neighbour's cat rather than him.