[cont] Juliette had a right to be hurt and angry, but the writers made her so irredeemable by having her so thoroughly betray Nick (and his mother, who did nothing to her). Adalind was kinda expected to do bad things, as she was villian for a time, but Juliette was the love interest. The one who was supposed to care about Nick. She was also friends with Rosalee yet she hurt her and tried to have Nick shoot Monroe. I just think the writers made it too easy to hate her.
This is one of those rare cases where I don’t actually think the blame falls completely on the writers for the way Juliette is viewed by a certain (very loud) section of the fandom (although I do blame them entirely for making Nadalind in any way canon even for a moment). Because if you’re not watching Grimm with misogyny goggles on, Juliette is no more hateful or horrible than any other character on the show.
I wrote a post on my personal blog a few seasons ago about the reasons Juliette is hated more avidly and consistently than other character on the show–long before anyone actually had anything like a reason. You can read that post here if you’re interested. In summary, Juliette is hated more than Adalind or Rosalee, or pretty much any recurring female side character, because she commits the apparently unforgivable sin–to a misogynistic audience–of being a female love interest with thoughts, desires, goals, and emotions which occasionally conflict with or challenge those of the male protagonist.
I would also argue that Adalind has done a lot of things before the oft-mentioned season three finale that were not done under duress. She did horrible things for power, for Sean’s attention, literally as part of her daily job, or just because she was told to. The fact that she did one of the many horrible things she’s done under duress doesn’t erase all the other awful things.
Nor does it help her case that she was still attacking one of the people she’d hurt most and taunting them with what she’d done “under duress” a few episodes before she suddenly decided she wanted to change…a growth spurt in character development which coincided suspiciously with needing help from all these people she’d hurt.
Now, consider the situation Juliette was in when she enacted her vengeance in season 4. She was under the thrall of powers that canonically influence people to do terrible things. She was suffering these powers not as someone who was born a hexenbiest, but as a regular human subject to the “side effects” of a completely experimental, untried, unpredictable set of magical circumstances.
Add to that the fact that in the span of a few days she was made to feel unwelcome and unsafe in her own home, lost her boyfriend of seven years and any concept of the future they might have had, and found herself lacking the support of any friends she thought had any hope of understanding what was happening to her. Juliette was in an extremely bad place, both mentally and emotionally, when she did the things she did. And it’s telling that she specifically attacked the things and people that symbolized what she (not incorrectly) saw as the source of all her pain: Nick’s life as a Grimm.
That doesn’t make the things she did okay, but it’s very much up for debate, on both a canonical and also a meta level, at this point whether Juliette can truly be held culpable for all the things she did–or whether the rest of Team Grimm can be truly blameless.
To be fair, Adalind had also lost a lot when she went on her vengeance spree…but recall that she was not under the influence of hexenbiest powers when she put Juliette in a coma. A coma that resulted in her losing all memories of Nick and developing a dangerous magical obsession with Sean that could have killed them both.
Juliette did the things she did because she was scared, angry, alone, grieving, and under the influence of dangerous, uncharted magic. Arguably, her emotions directed her destructive behavior’s targets but did not cause the destructive behavior itself. After all, Juliette has been all of those things before, and has never attacked the people she cares about or blamed them for her own pain. In fact, before the hexenbiest powers it was much more in-character for Juliette to put aside her own concerns in favor of what her friends might need at any point in time.
Adalind, on the other hand, did what she did because she was scared, angry, alone, grieving, and that was her pure human reaction: to lash out and hurt people, including innocent people who’d never done anything to her. Her emotions may have directed her destructive behavior’s targets, but Adalind herself caused the destructive behavior. She had no powers to be her excuse or explanation.
The reason fandom finds the one lovable and the other unacceptable is that Adalind was introduced as a villain and thus allowed to do her villain thing with audience impunity, whereas Juliette was introduced as a love interest and vilified by the audience every time she dared to do anything that wasn’t 100% sycophantically in line with whatever Nick might want or need. Add in a heaping dose of rape culture encouraging audiences to see healthy relationships as “boring” and aggressive, violent ones as “passionate,” and there you have it: the main reason many fans prefer Adalind over Juliette as Nick’s endgame love interest.