I'm not really shocked when people deny genocides that happened more than 100 years ago when we have ongoing genocides in the very PRESENT that are being denied although we have undeniable evidence in high quality footage. It's also quite bizarre when some, rightly so, demand Turkey to acknowledge the Armenian genocide, but don't have much to say about Turkey's refusal (among other nations which somewhat economically depend on China) to acknowledge China's genocide of the Uyghurs or God forbid Israel's genocide of the Palestinians.
Anyone who denies one genocide loses any credibility and right to ask others to acknowledge their 'favorite' genocide they like to mention when it suits their interests.
Most of the time the defense will be based upon a false understanding of what really constitutes "genocide". "B-But the population numbers are increasing" - Which might or might not be true, but that's besides the point:
"Generally speaking, genocide does not necessarily mean the immediate destruction of a nation, except when accomplished by mass killings of all members of a nation. It is intended rather to signify a coordinated plan of different actions aiming at the destruction of essential foundations of the life of national groups, with the aim of annihilating the groups themselves. The objectives of such a plan would be the disintegration of the political and social institutions, of culture, language, national feelings, religion, and the economic existence of national groups, and the destruction of the personal security, liberty, health, dignity, and even the lives of the individuals belonging to such groups." - Lemkin