It's not very bad, many persons waste their time, but you have access thanks to the computer (and internet) to unlimited information and knowledge quickly and easily.
It can be a disaster especially if people spend a majority of their time on it daily however it can be good because it does allow you to read news and communicate worldwide very easily.
Anything can be addictive. Computers are pretty far down on the scale of addictiveness. Drugs you have to ingest in some way. Computers you can not ingest.
You can become addicted to reading, sex, alcohol, food etc.
Computers don't bloody well kill anyone but food, alcohol and drugs can so who cares if people want to spend their time on computers. It's their choice and they aint harming people.