Comment by Kim_Bruning

The vast majority of articles that get deleted are speedy deleted. This can be due to things like obvious vandalism (things like teenagers putting swearwords etc.) , articles about random people that are really just a breach of privacy and not helping anyone, strange conspiracy theories, advertising, spam, self-aggrandizement, copyright violations, etc. In short: Things that don't belong in an encyclopedia. This is why the history is normally hidden as well. [1]

The articles that get any sort of discussion at all are the edge cases where a single patroller by themselves can't make up their mind. And due to the nature of being edge cases, they can indeed attract quite some discussion!

If an article is at all redeemable, it is (should be) kept and expanded instead.

[1] Normally you want to keep around a copy of "deleted" content in case someone wants to do some sort of check or audit, or might perhaps want to salvage some data that might still be useful. In certain extreme situations like particularly egregious copyright violations, doxing or someone putting up CP or what-have-you, page history access can be denied to admins as well.