I haven't read through all of the responses in that thread yet to see if someone else addressed the point I'm about to make, but the definition used in the UN resolution is intentionally vague.

To give a brief history of where genocide originates from as a legal concept to the definition we have now, we're gonna have to talk about legal scholar Raphael Lemkin.

When Lemkin was studying genocide and attempting to draft a law that would cover all aspects of what makes something a genocide, he made note of a few things. One was that genocide as a crime was unique in the sense that the entity carrying out this crime was usually itself a nation-state or working on behalf/under the jurisdiction of a nation-state. Therefore, a legal solution to address/prosecute a genocide could not be administered as a national law, since if a nation was in the process of carrying out a genocide then the entity responsible for prosecuting that crime is already complicit in the crime. So in order to pass a law that would have any effect with regards to deterring/prosecuting a genocide that law would need to be enforced by an international body.

This led to Lemkin petitioning the UN to adopt the UN resolution on genocide. In the original drafts Lemkin presented to the UN when he proposed that they adopt this resolution, the legal definition of genocide that he drafted was far more broad than the definition the UN ended up adopting. It included provisions for stripping a national group of cultural practices and the ability to participate in society in their native language, campaigns of forced assimilation, economic policy that created barriers to the economic participation in society on the basis of nationality/ethnicity, theft of land/wealth based on nationality/ethnicity, and in general any act that was designed to weaken a specific national group in whole or in part in order to benefit the national group who was wielding state power to carry out these acts. These acts of discrimination/disenfranchisement could eventually lead to the slaughter/destruction of the national group being targeted, but in Lemkin's original drafts the slaughter/elimination of a national group was not necessary to prosecute something as a genocide. An attempt to infringe upon and disrupt the pattern of life of a given national group targeting people on the basis of their identity as part of that national group was sufficient to prosecute something as a genocide.

The problem with this definition is that in order to be ratified in the UN, it would need to pass a vote from the UN member states. And a large number of countries refused to ratify the resolution with its original wording because they were concerned that the existing wording could be used to prosecute their country. With notable examples being the USA still having Jim Crow laws in full effect at the time, as well the legal status of Native Americans and "Indian Reservations" being called into question by the original resolution, as well as the legal status of every colonial government held by the various countries of Europe falling under the jurisdiction of the original resolution.

Lemkin fought hard to keep those provisions in the resolution he drafted, but eventually relented because he saw a weaker resolution with the force of international law behind it as being preferable to a stronger resolution that only had partial support. But the result is that the current language of the UN resolution on genocide is the result of a process where the criminals were allowed to rewrite the law until they were no longer guilty.

Because the remaining language is so vague, it gives cover for powerful countries to legally squirm their way out of repercussions on pure technicality, while also giving those countries the ability to weaponize the resolution based on technicalities to accuse their geopolitical opponents of genocide as a pretext/justification for intervention and adversarial foreign policy. For example, the language in the UN resolution which references attempts to prevent births in a national group has been used in international politics to target developing countries. As different areas of a country become more economically developed, that development also usually results in greater accessibility to medical resources, which includes contraceptives. As families are given more control over when they choose to have a child, the overall effect is usually a decline in birth rates among a given population. This data showing declining birth rates will then be presented as evidence that a country's policy is resulting in births being prevented in a national group, which is sufficient grounds for accusing a country of genocide under the current language of the resolution. And whether that accusation is ultimately prosecuted by the UN, the pretext of "Human Rights Concerns" is usually all that countries like the US need in order to initiate "Non-combatant warfare" against a country in the form of imposing unilateral sanctions on them as a way to gain leverage against a geopolitical entity that controls resources which are valuable to US state/business interests.