Mad because :
1. They can't afford bitcoin.
2. Too late to the trend, they are jelous of peoples who get into the trend long before them so that those peoples earn more than them.
3. They want to make peoples leave bitcoin and chose other digital currency which they have bought with the intention to raise its value, greed are disgusting when are too much that you do anything to get what you want.
4. Etc you can think of.
So don't mind those peoples, only sell your bitcoin or buy it when you see profit.
I do believe also that people who are mad on bitcoin are those people who don't really know what bitcoin is and some maybe are jealous to those bitcoin holders as butcoin recently rise high . they maybe don't know how to earn bitcoin thats why they are telling bitcoin as a scam or anything that is not good for bitcoin.maybe they are too late as well to invest as bow the price of bitcoin is too high. so dont mind them as long as you have trust in bitcoin you will earn from it.