Joann Lee Kelly -- aka Buku Abi -- shared a long, thoughtful message on Instagram Thursday, apologizing for taking so long to say something, explaining she's been searching for the right words for days.

Abi expresses sympathy and devastation for all of the women who've been allegedly victimized by her father, and makes it clear that she, her mother and siblings don't condone any of his negative behavior -- past or present.

She also suggests for that reason, she and her family have not had any relationship with Kelly for years, saying ... "Going through all I have gone through in my life, I would never want anyone to feel the pain I have felt."

Buku adds ... "The same monster you all confronting me about is my father. I am well aware of who and what he is. I grew up in that house."

Kelly's daughter says she's chosen to stay out of the spotlight because it's better for her healing process, and the constant reminders of "how terrible my father is" aren't good for her ... so she has to do what's best for herself.

We spoke with Buku back in April about allegations against her dad -- and she didn't say much -- her attitude has clearly changed.

As you know, Kelly's surrounded by controversy and allegations of sexual abuse and predatory behavior in the wake of Lifetime's docuseries, "Surviving R. Kelly."