Step Mama Question

I'm new to this step parent thing. My stepdaughter is 10 months old. About a month ago my fiancés ex sent us a video of the baby starting to stand without support. My problem is, she had a lolly pop in her mouth. I told my fiancé that he should say something to her because it's extremely dangerous. She was standing next to a table and all I could picture was her falling and getting hurt/choking. He kind of blew it off.

I posted this in another group and was basically told "not your child, not your problem". I understand things will come up that I don't agree with and have no say over, but this is something that could hurt her. And just because I am not biologically related to her, doesn't mean I don't love her like my own children.

Am I wrong for expressing my concerns? Should I really feel like "not my child, not my problem"?