Was my sister making a joke or making fun?

My sister dislikes my boyfriend because of past events. I uploaded a Snapchat video of us where it puts makeup on you to Facebook. My sister commented “I always said I would support my sister, even if she was lesbian.” I interpreted it as a joke because the app put makeup on my boyfriend, it’s not like he was REALLY wearing makeup. I would laugh if he uploaded a video of me with a mustache and beard and someone called him gay. My boyfriend thinks she was making fun of him and got upset. How do you interpret this?