Why is there no Stack Exchange site dedicated to Q&A about Hacking? Is this topic included in any other site? Where can I ask about this topic?
There is Information Security SE which might answer your queries
Information Security Stack Exchange is a question and answer site for information security professionals.
And there was a proposal in Area 51 related to hacking and pen testing but it didn't get much response.
In addition to InfoSec SE, there is also Reverse Engineering Stack Exchange for "researchers and developers who explore the principles of a computer system through analysis of its structure, function, and operation."
On-topic questions include looking at executables files under-the-hood and packet and firmware analytics for a wide variety of platforms.
Just know that general "hacking" questions (whatever that means) would be off-topic. Reverse Engineering SE is for specific issues and real problems, not general or broad questions.