I am not surprised. Sri Lanka shares a lot of culture and history with India. Afterall one of the origin stories of sri lanka is king Vijaya was banished from India and sailed to Sri Lanka where he met the locals then and established the kingdom that later became Sri Lanka.

When I am working abroad and miss home food and I can't find a Sri Lankan shop, I often substitute it with Kerala food, which I believe some of our main dishes are inspired from. Both Kerala food and Sri Lankan food makes heavy use of coconut milk in preparing their dishes.