Agreed. 1000% Agreed. No piece of media is above criticism, and Acotar, that markets itself as a feminist novel, and has themes of slavery, feminism, overcoming trauma, mental health and healing, has opened itself up to criticism under those lenses. You can't add complex themes to a book then argue it's 'not that deep' because it is now.
Mental health isn't some kind of trend that you can add into a book to make people relate to the characters, or give them quirks and expect nobody to examine it deeper. When adding these themes into books, when talking about slavery, and freedom, autonomy, healing, alcoholism, war, trauma, etc. You need to take great care in how it's portrayed, to avoid spreading misinformation or dangerous ideologies. Because, like it or not, these things can affect people.
People in abusive situations, or who see themselves in characters like Nesta or Tamlin, will see the way these characters are treated by both the readers and the fandom and it will affect them in some capacity. They will see Madja, a medical professional, keeping such important secrets from her patients, Rhysand hiding it from the supposed love of his life, who previously made clear how much she values her freedom and choices, Cassian laughing at Nesta's pain, then admitting that it made his day, and they will think that these things are normal or good representation of relationships and how health professionals should behave.
Doctors keeping information like life threatening pregnancies from their patients is unethical and illegal.
Giving that information to anyone but your patient, especially while not telling them, is unethical and illegal.
Keeping that information from your partner is abusive, and dangerous, also illegal.
When you are (unethically) in charge of somebodies life, and trying to help them deal with alcohol dependence, and trauma, or any other struggle, ignoring their desires, disrespecting their space, and laughing at their pain is abusive.
If ACOMAF is Feyre's healing journey, and ACOSF is Nesta's, then audiences have a right to analyse how well the story does that. Criticising the way in which it's represented, especially when it has such a large fan base, is necessary.
In which universe is it okay to perpetuate children earning the love of their parents, or in any way assuming that the child failed the parents.
What universe excuses laughing at or being amused (even if you don't verbalise it) at the physical pain of another person, especially when you think that it was a result of somebody you know, and consider family, assaulting them.
In what god damned universe do we say that a man drugging a woman and forcing her to wear practically nothing (lingerie would give you more coverage than the sheer scraps of fabric he forced her into, after ordering two women paint on her against her will), and publicly perform for him and and his peers, even when she threw up or collapsed, in any way okay?
The issue isn't even that these scenes or plot points are included. Not really. I mean, take a look at dark romance. There are so many books that are much darker than acotar, with just as many, if not more fucked up things happening in those books, often to the mc by the love interest. The difference between that and ACOTAR, however, is that the whole point of dark romance is knowing that it's fucked up, and morally reprehensible.
The readers, the author, and the characters/narrative in the book, are all well aware of fucked up those things are, and they don't pretend otherwise. In fact, the narrative itself continues to remind us of how dangerous or fucked up these things are. The author and the readers know that these characters are neither good people, nor are they doing the right thing. They don't perpetuate the behaviours seen in the book. They don't try to argue why those actions are acceptable. They understand how triggering and dangerous these things, and real life people who do these things are.
THEY AREN'T PRETENDING THAT ANYTHING THE MCs DO IS EVEN REMOTELY OKAY!
No piece of media, especially media with such heavy themes, has a right to be critiqued and called out when it doesn't do those themes, or people in those demographics justice.
Don't excuse actions that are inexcusable.
In doing so, you also do a disservice to people who have been drugged, SA'ed, struggled with alcohol dependence, abuse, and have wanted to end their own lives. If you still want to like the character, go for it. Just don't pretend that what they did was okay. It's not. And pretending it is can be so very dangerous for those who are struggling.