Although it has not been a popular opinion on other boards, I actually am comending the writers for showing the nuances between Meredith's reaction to Thatcher's alcoholism and the chief's.
Meredith certainly has father figure issues, as would most women in a situation like hers. She has few if any memories of Thatcher as her father. When she does come back into contact with him she learns that he has a wife and new family, including a doctor daughter he is very proud of and adores. To her it seems like his drinking is just another excuse of why he wasn't strong enough to be there for her. There are obvious reasons that he wasn't there, but it still does boil down to the fact that Thatcher didn't fight for her.
Then you have the chief. They have always had a strange vibe between them. She knows how her mother felt about him and how that played out. At the same time this is also her boss. She grew up in a world where she idolized doctors. The voiceover talked about her getting medical gifts at Christmas and there was the episode with the Anatomy Jane doll. She's obviously going to look up him with a mixture childhood adoration, respect, and anger over his involvement with her mother. To me it makes sense that she would be a little bipolar with her feelings toward him. It's a complex situation.
I have two uncles who were or are alcoholics. Admittedly, I treated the two very differently. My older uncle abandoned his wife and two children and became homeless. He would pop up in my life from time to time wanting money or a place to stay. I was pretty mean to him, telling him just what I thought about him and his choices. He died in 2000 from complications.
My other uncle is still alive and drinking. I don't condone his drinking or like that he does that so much, but I also don't yell and scream at him. One of the biggest differences I guess is that he and his wife both drink together. He hasn't abandoned his children. He still holds a steady job and is living his life.
That is to say that I'm glad they haven't totally destroyed this story yet. I am able to relate to the complex feelings in it.