Diff Agency Front End Developer interview questions

Had a call with HR, we talked about previous and current work experiences, then I had a test to do, a countdown timer built with any framework (React, VueJS,...). Several days after I had a video chat with HR and Dev Lead, we talked about the test and how I can be integrated into the team. At the end they didn't take because I'm too attached to React (which I've never said, I said that I was flexible) and they prefer to take someone who made the test in vanilla (HR was very vague about the stack they use, she don't know if they'll use React or VueJS), they want someone to stay and not get annoyed of building Shopify themes, because yeah the position is about to build Shopify themes mostly no engineering, you will do UI/UX annoying stuff. The process was fair the only feedback I would provide is, if the candidate seems to want to do more than building Shopify themes don't waste his time by making him test and useless calls.