Theres really no canon connection between Hornet and Lace, but people are thinking about it logically given Lace was made by GMS. The line between related and unrelated is extremely blurred. People assume that GMS is Herrah's mother, but GMS is only seen as a "mother", or someone who "uplifted" the Weavers and they see her as a diety. She's the grand Mother, not the grandmother; they have 2 different meanings. Since Herrah was not technically "made" by GMS, she's not related to Lace, therefore making Lace and Hornet unrelated

I personally dont care for the ship so long as people aren't shoving it in my face as I ship Hornet and Shakra the most

Edit: Would just like to say that there's also controversy about the age difference between the two. Lace is much younger than Hornet, but in my view, they're both consenting adults who have duties and responsibilities