The plane was in an unintended aircraft state during your checkride. Specifically, there was a taxiway incursion at the very least, and maybe a runway incursion depending on where the captain turned the plane. Regardless of the reason, you didn't stop him. That alone is a fair bust.

When you're on the line, you'll run into the same thing. Most captains know what they're doing. There are a handful who don't, and you'll be responsible for making sure that they don't get you violated or worse.

You'll probably find yourself on a slippery slope if you challenge this. Your best bets are to own the failure, learn from it, and not make the mistake again. If you keep the rest of your record clean, then getting an interview down the road with a major shouldn't be as hard as some of these other guys are saying.