A "bad neighborhood" are sites like link farms and low quality directories that are very spammy. A link from one of those sites to your webpage can have a negative effect on your SEO instead of positive one. A lot of blackhat SEOs who are just trying to make a quick buck will have their clients linked from bad neighborhoods and charge for the backlinks.
It should not be treated as black hat technique but it certainly would not provide you much help too as you are placing on such page that has lots of links from other niche and of very low quality websites so you should avoid getting such backlinks and should focus only on quality backlinks from quality websites related to your niche as when it comes to backlinks
" bad link neighborhood is the past of black hat SEO,Bad link neighborhood refers to linking to sites that offer illegal content. Illegal content are content that promote negative influences such as cigarette".