Great Moravia. You know the state which had its core in modern day moravia and slovakia.
And double post since I did a missclick: Great Moravia existed for 70 years. Main portion of CK2 is taking place over 100 years after it fell.
Once again, your knowledge is clearly lacking and you are doing the same mistake done some time ago by whoever created Moravian culture and that is assuming that since land was controlled by a political entity long ago, its people should identify themselves with that entity.
Simply put, that´s now how it works.
EDIT: Also, you´ve got quite an interresting fallacy going on there. You say that entirely different development of Moravia and Slovakia after 906 is not a reason to differentiate between two peoples because political/economig development =/= cultural, yet you seem to be basing your entire premise of Slovaks = Moravians on existence of political entity created through conquest of Nitra by Moravia.
Also, a study (no idea whether it´s on the internet though) by Slovak archaeologist Tomáš König comparing finds from Slovakia and Moravia suggests that there were differences between regions of Moravia and Nitra, as Nitra seemed to have been poorer, less Christianized and less urbanized compared to Moravia during the time they were this supposed "core" of Great Moravia.