This is good news. You have to earn your links through great very good/superb content. Any link buying/exchanging links undermines the whole process.
Google also has to be clever enough to determine when a site owner is getting spammed with bad links. It should not be the job of the site owner to mine for bad links and send out emails asking for them to be removed, or even disavowing them. This is just wasted time that could be spent doing something more useful.