You may have given him a great idea he chooses to dismiss because he will use it and give you no credit. It may be he is just didn't want to get into a whole dialogue with you about it, so he ignored you, which was rude. It may be he gets lots of unsolicited contacts from people, so he ignores them. It may be simply he has poor social skills.

You didn't do anything wrong. But you did send him unsolicited advice, which is a slippery slope. He may have been suspicious what is in it for you. He may have been afraid to comment because of fear of getting sued for whatever reason.