Why can't it be both good and bad for you? Water is also good for you but you can also die from drinking too much. Same with oxygen. Anything that's good for you in moderation, can kill you when consumed in excess.

The article doesn't say that any amount of coffee is bad for you, it says "chronic caffeine consumption is bad for you" which again, should be common sense. Chronic consumption of anything is generally bad for you.

It may very well be that light to moderate consumption could be beneficial at the same time as chronic being bad.