Well, yeah, but like... [Henry takes a moment to think about this.] You're supposed to give someone a name that's only theirs. It's like part of their identity. So by calling her 'Mama', you're basically saying that she doesn't have her own identity -- the only thing important about her is her relationship to her kid.
And that probably doesn't feel very good, for her.
the absolute garbagiest
And that probably doesn't feel very good, for her.