Based on this paragraph, what does Briony mean when she says at the conclusion: ""I like to think that it isn't weakness or evasion, but a final act of kindness, a stand against oblivion and despair, to let my lovers live and to unite them at the end."

Context: The final section, titled "London 1999", is narrated by Briony herself in the form of a diary entry. Now 77, she is a successful novelist who has recently been diagnosed with vascular dementia, so she is facing rapid mental decline. The reader learns that Briony is the author of the preceding sections of the novel. Briony attends a party in her honor at the Tallis family home, where the extended Tallis children perform The Trials of Arabella, the play that 13-year-old Briony had written and unsuccessfully attempted to stage with her cousins in the summer of 1935. Leon and Pierrot are in attendance, Jackson is fifteen years deceased, and Lola is alive but does not attend. Finally, Briony reveals to the reader that Robbie Turner died of septicaemia on the beaches of Dunkirk, that Cecilia was killed several months later when a bomb destroyed Balham Underground station during the Blitz, and that Briony's story of seeing them together in 1940 was a fabrication. Briony did attend Lola's wedding to Paul Marshall, but confesses she was too "cowardly" to visit the recently bereaved Cecilia to make amends. The novel, which she says is factually true apart from Robbie and Cecilia being reunited, is her lifelong attempt at "atonement" for what she did to them. Briony justifies her invented happy ending by saying she does not see what purpose it would serve to give readers a "pitiless" story. She writes, "I like to think that it isn't weakness or evasion, but a final act of kindness, a stand against oblivion and despair, to let my lovers live and to unite them at the end."

Answer: Based on this passage, Briony is explaining, as the narrator of the novel, why she fabricated the portion of the story involving the reunion of Robbie and Cecilia.