Every large Russian city has some monument dedicated to Soviet political prisoners.

Plus sometimes there are monuments related to more specific ethnic/politican groups if they happened to suffer at that place.

Find one about Armenians in Turkey?

They can (the nature of sovereignty is such that a sovereign can outlaw anyone doing anything), though they may have trouble enforcing the law by which they make that illegal. Foreign states have been dragged into another state's courts for violations of the latter state's law, though (this is particularly true when the latter state is the US), so its not necessarily the case that there is no possibility of some accountability to such a law.