I wouldn't necessarily call creating backlinks in bulk "black hat" seo, it can be more spam than black hat SEO.
Typically, creating a lot of backlinks in bulk would be considered spam because it's difficult or nearly impossible to create a lot of backlinks that are all high quality backlinks.
If you have lots of high quality websites, then a sitewide link on all of those high quality sites can generate a lot of backlinks--but that's not the norm. An example would be when Yahoo links to one of their partner sites or they link an entire section of their site (sports.yahoo.com) to a partner.
When it comes to black hat, those techniques are much more sophisticated than merely creating bulk backlinks or spamming links all over the place.
So, to answer your question: creating bulk backlinks is typically search engine spam, and not "black hat" SEO.
SEO since 1996, I've been doing internet marketing. I have the experience as an SEO expert
, as well.