I think the best way to shut up bitcoin haters is to prove that you are earning on bitcoin. When I was starting at bitcoin, there are a lot of negative comments from my friends and they were always telling me to be cautious. Only a few of them supported me and those people are investing on bitcoin as well. They are earning enough money for their needs and they never regret investing on bitcoin even if the price goes up and down.
In my own opinion, we don't need to shut them up. All we need to do is to focus on our work in bitcoin and don't mind them because they can ruin your concentration in bitcoin. I think proving them that we earn money in bitcoin is enough for them to shut up because they don't believe that we earn money in bitcoin. So all we need to do is to prove to them that we earn money in bitcoin.