Should hatred exist or not?

it should not but always will be. people are social animals that will hate anyone that disses or interfere with them as a natural human response

Changes of that scope would result in unexpected consequences. Humanity would be changed, probably at its core. We might be better for it or worse but we certainly wouldn’t be the humanity we know and love. We might go extinct. Or not. Beware of unexpected consequences.

With everything human, there is our animal nature and our human capacity to exercise self-control, resist temptation, and rise above more base instincts.

Hate is a natural response to fear and a byproduct of the will to control and police our lives against perceived threats.

However, the question is whether we can rise above the emotion, hate, and simply control and police threats without experiencing emotions like anger and hate; and if we can, is that a good thing necessarily?

For example, if we decided rationally that a certain number of people had to be eliminated to achieve sustainability or national stability or some other political cause, would it be better to simply euthanize the targeted people without any emotion, or to create a war situation where anger and hate are evoked to motivate fighting and procure the killing that way?

Arguably, humans feel better about war than they do about genocide or other mass euthanasia, so does that mean they also prefer passionate fighting over dispassionate execution of political obstacles? If some government began a mass-euthanasia program but there was no racism or other hate involved, would that be considered less offensive than when genocide is perpetrated with hate?

These are really hard and uncomfortable questions to contemplate, and hopefully contemplating them wouldn't lead anyone in the direction of becoming more comfortable with killing, etc. When you really want to explore the place of things like hate and killing in human existence, you have to reflect on historical examples as well as hypothetical scenarios.