At least as a start: /u/yodatsracist has a great in-depth response to a previous question about why Turkey is so defensive about the Armenian Genocide here which covers some of what you're asking. It's a two part reply which also includes some links to other posts and questions.

One of the links is to a short discussion between /u/yodatsracist and /u/Georgy_K_Zhukov about some of the underlying factors behind denial and the controversial nature of even discussing the Armenian Genocide in some contexts (nationalism, the realpolitik of modern diplomacy meaning many countries won't challenge an important regional power/ally like Turkey about it, possible territorial and other considerations, etc.).