This is a 100% contrived, but here's an example...
- I run a dev team largely using Microsoft tech
- You are a Java developer
- I had a Java developer try out the Microsoft stuff, and quit because they decided they didn't wanna go all in on C#
- If you're work experience in largely in Java, but I see you spending a lot of time writing C# in your personal time, or somehow demonstrating a passion for you, I'm more likely to think you'll be a fit.
Maybe asking people to demonstrate a passion for tech is related to feeling defensive about that tech. Plenty of back-end-y developers trash talk CSS and JavaScript. Someone who works on front-end stuff all day long might not like that trend, so they filter for people excited about JavaScript, and I can't say I'd blame them for that.