Well, let's say this is a hypothetical conversation:
Interviewer: So, what do you think about abortion?
You: I see strong arguments both ways. I personally have a sister who had an abortion and understand that, for her, it was the right decision due to X and Y reasons. This experience helped me to see one side of the argument. On the other hand, I can see that people may object for X, Y, Z reasons. Etc. Etc. Etc.
Describing a personal experience often makes an argument stronger as opposed to weaker. As long as you had a balanced, rational justification you should be just fine. I appreciate when interviewees explore both sides of a question and personal anecdotes often stick with me and make the interview more memorable. Applicants will, understandably, have their own stance on polarizing topics and it is often obvious. So they don't expect you to be completely middle-of-the-road.
As far as rambling, yeah, people can do that at times. It's better than being silent. 😉