“It’s always easier to hate than to forgive, isn’t it?”

This seems to be derived from a statement attributed to Rear Admiral Grace Hopper, and which she regularly used in her public addresses: "It's easier to ask forgiveness than it is to get permission."
Vorkosigan Saga, A Civil Campaign (1999)

Source: 1800s, Jerusalem The Emanation of The Giant Albion (c. 1803–1820), Ch. 4, plate 91, line 1

Source: CAT'S EYE.

Source: Lion's Heat

As quoted in the U.S. Navy's Chips Ahoy magazine (July 1986)
As quoted in Built to Learn: The Inside Story of How Rockwell Collins Became a True Learning Organization (2003) by Cliff Purington, Chris Butler, and Sarah Fister Gale, p. 171
The future: Hardware, Software, and People in Carver https://books.google.com/books?id=5Q7uAAAAMAAJ, 1983
Actually attested since mid-19th century.
Variant: If it's a good idea, go ahead and do it. It is much easier to apologize than it is to get permission.
Variant: That brings me to the most important piece of advice that I can give to all of you: if you've got a good idea, and it's a contribution, I want you to go ahead and DO IT. It is much easier to apologize than it is to get permission.
Source: https://quoteinvestigator.com/2018/06/19/forgive/

The True Believer (1951), Part Three: United Action and Self-Sacrifice
Context: It is easier to hate an enemy with much good in him than one who is all bad. We cannot hate those we despise. The Japanese had an advantage over us in that they admired us more than we admired them. They could hate us more fervently than we could hate them. The Americans are poor haters in international affairs because of their innate feeling of superiority over all foreigners. An American's hatred for a fellow American (for Hoover or Roosevelt) is far more virulent than any antipathy he can work up against foreigners. It is of interest that the backward South shows more xenophobia than the rest of the country. Should Americans begin to hate foreigners wholeheartedly, it will be an indication that they have lost confidence in their own way of life. <!-- p. 96

Source: The Long Hard Road Out of Hell

Source: Abandon