Warning: The following paragraphs may contain spoilers for the third season of Fridays For All Mankind. Proceed at your own risk!
The viewer's displeasure with Danny and Jimmy Stevens is a good thing, according to the showrunners for For All Mankind.
When Danny's childhood best friend, Karen Baldwin, was found to be his first suspect in the second season, the elder brother made his first public appearance. As the current third season begins this summer, the subject continued to rear its head. Although nearly ten years had gone since the tryst and Danny had gotten married to an age-appropriate woman, he still wanted Karen, who had recently broken up with a one-time hookup.
Danny's uneasy behavior grew as the season progressed: he cheated on his wife, was arrested, secretly watched Karen and Ed's video messages to one another, developed a heroin addiction, lashes out against his commander, Ed, and caused a catastrophic mining accident on Mars that cost several astronauts their lives.
Jimmy's younger sister Jimmy joined a group of conspiracy theorists following his parents' death on the moon 10 years prior. The extremists fabricated Jimmy and exploited him to gain access to the Johnson Space Center, which they bombed in Season 3, killing Karen and former astronaut Molly Cobb, among others. (Get more information on those victims here.)
Matt Wolpert and Ben Nedivi, co-showrunners and EPs, both brothers arcs this season were met with viewer displeasure over the characters' increasingly bad choices.
The Stevens siblings' strong response from the audience is a welcome one, because to me and to [co-creator] Ron [D. Moore] early on, passion is passion, according to Nedivi. When you're getting passionate reactions from people, you're doing something good.
Danny went through a rough patch when Gordo and Tracy died, so its only natural that he and Jimmy would be messed up. Just losing your parents at that age, trying to live up to their legacy, but also carrying around that ghost I can't imagine [how difficult that must be], Nedivi thinks.
Dannys portrayer is praised by Wolpert for taking on the task of portraying the ludicrous young astronaut and bringing pathos to his hardships, according to the author. That character is easy to hate, but he also goes through so much, and he is bringing that suffering to life more and more as the season progresses.
According to Wolpert, Danny made one excellent decision: When he and Ed were buried alive in a Helios Mars habitat in Episode 8, it appeared that Danny was on the verge of confessing about his affair with Karen. However, even after they were rescued, Danny never disclosed to Ed that he was the one who slept with Karen.
I'm not going to say that [there is] a redemptive quality, but Wolpert says. If Danny said [the truth] to Ed, he would be completely unredeemable. There is an element of] he wanted to take everything off his shoulders, [but] knowing that that would destroy Ed in a further way, he's keeping it [to] himself almost out of kindness.
Danny admitted to being to blame for the mining accident, causing Ed and Danielle to send him to Mars, where they will send him monthly supplies, according to viewers. (He certainly attempted to do so when he volunteered for a dangerous mission with Eds pregnant daughter, Kelly). Ultimately, the showrunners chose not to give Danny an obvious redemption narrative.
We planned to tell a tragic tale of the character, and that's why the end felt appropriate for him, according to Nedivi.