That is a reality and not just to your experience. The fact is that lottery is a gaming prize which winners are taken unaware even without expectation that your tickets is a goal for the draw.
It is shuffled by the lottery conductors and then after, the winner is notified which gives it a room for scammers to invade in by contacting their targets.
So you were able to find them being fake when they sent you the mail unknowingly to them that you don't participate in lottery games.

In gambling, you would have to play and expect winning in a specific time of which you can also keep you games on track to know your faith if staked on live games which by yourself you can detect if you won or lost and the casinos has no need to contacting you for your wins.