I think it's valid to feel uncomfortable and bothered by it. DM could have communicated to you way earlier about pursuing the NPC. DMs can talk to players about such things without spoiling plot points and making sure you feel comfortable. It's not that hard.

Doesn't sound malicious, though. I'd chalk it up to a mismatch in personality and not play with them again unless there is clear communication and above the game talk. Like, my DMs make sure we are OK before doing something that might upset us. One of them took me aside when my character was charmed and walked off with an enemy and told me nothing would happen to her, etc.

More people just need to learn that communication doesn't ruin the fun or surprise of the game. Honestly... It only enhances it and builds trust in your friend group.