I wasn't trying to imply anything about you personally being a jerk or otherwise. Of course they're not assessing you on engineering ability! They're assessing

I wasn't trying to imply anything about you personally being a jerk or otherwise. Of course they're not assessing you on engineering ability! They're assessing your soft skills, like how you are at talking with people in other departments. It's kind of like if you go on a date with someone and you're rude to the wait staff, that's a big red flag, right? You're not going to ask the server if you should plan on a second date, but their presence in the interaction gives you information.