This is such a common situation, and very tricky! It is wonderful that you are thinking about how to ease your daughter’s experience of family member’s beliefs and comments. Some parents do distance from family members during the period of time when extended family is not yet aware, and so continues to express beliefs or ideas that are unintentionally hurtful. However, there are a couple things you can do to help your daughter feel loved and affirmed even in the face of these comments.
1. If your daughter has not yet chosen to come out, you can speak up and respond to these comments in ways that are supportive of LGBTQ people (without outing her). For more information about this, see Speaking Up: Independent Actions.
2. You can have the “people say stupid stuff” conversation with your daughter, as you mentioned. The benefit of speaking with her privately about what she may hear is to help her put the comments into perspective and avoid taking them personally. In other words, you can help her understand that these comments likely stem from an individual’s long-held, possibly unexamined ideas and and viewpoints, and may not have anything to do with feelings about her as an individual. It may also be helpful to reiterate that you do not agree with the statements and if she ever wants to discuss what she hears with you, you are open to doing that.