Captain America's decision to go back to the past and reunite with Peggy at the end of Avengers: Endgame directly contr...
Avengers: Endgame is the great farewell and gratitude of the MCU (Marvel Cinema Universe) for the first members of the Avengers group. If Iron Man (Robert Downey Jr.) died, then Captain America (Chris Evans) had a perfect ending when he returned to the past to complete the dance with Peggy Carter (Hayley Atwell). However, this completely contradicts the "morality" he said earlier.
Of course, Steve and Peggy's unfinished love story is too popular among Marvel fans. The end of Captain America: The First Avenger (2011) split them, but the two still love each other passionately. Peggy contributed to the founding of S.H.I.E.L.D to find a way to rescue his lover, while the image still appeared in Steve's mind through the MCU movies. But after Peggy died in Captain America: The Winter Soldier (2014), Steve was able to move on.
This is also an important theme in the first episode of Avengers: Endgame. After the snap of Thanos (Josh Brolin), he held many meetings and advised everyone to move on, ignore the past, accept the loss of loved ones. If he did what he said, Steve should have accepted that his life with Peggy in 1945 was over. Especially when Steve gave Sharon Carter (Emily VanCamp) a kiss at Captain America: Civil War (2016).
However, as soon as he discovered the opportunity to reunite with his lover, Captain America suddenly gave up everything to return to the past. Even he ignored the responsibility of an Avengers to the dangers in the future. Of course, Steve once confided in Natasha (Scarlett Johansson) that he always told people to let go of the past, but they themselves couldn't do it. However, at the moment, he is talking about Thanos' snap, and his feelings for Peggy are another matter.