The story takes place in a town of about 80,000 people. That's, on average, 1600 people that disappeared. It's too large to not go universally noticed by everyone.
Imagine, some of those 1600 people were driving vehicles. Some where operating dangerous machinery. One could have been a bus driver. One could have been flying a plane. There would be accidents leading to deaths and injuries.
In our network of society, it doesn't take much disruption to have an effect on a large number of people. If some guy killed himself today in his own home, that would effect his immediate family deeply (could be on the order of a dozen if he has a wife and children and parents and siblings), plus extended family somewhat, plus friends, plus coworkers. If he did it in public, the people witnessing would also be effected.
If thousands of people in a community died, that would be an incredible tragedy that effects the entire community. People would eventually cope, though. If it was, say, a terrible accident, people know that these terrible things happen and you get through them. Some might turn to religion when they weren't before.
If thousands of people simultaneously and instantaneously disappeared, people would not know what to do. Imagine you're a parent. People can't cope because they can't explain what happened. Nothing in our experience can adequately explain what was witnessed. People would be lost, hurt, searching for answers.
2% is a pretty huge number when you start to think of all the people that any individual effects. Something like 10% would be catastrophic. It's also not, of course, equally distributed in every possible grouping of individuals you can come up with. Some people would know no one that departed, and some would know many. Some individuals could lose their entire family. Some cities may lose 5-10%, while some lose almost none. But even those that didn't directly know anyone are still affected.