Question about completing co-op games

For Treasure Island, two more people besides me need to log in to complete the game... Is it a mindset of trusting others and wanting to piggyback on the completion? It's really annoying. ㅜㅜ I'm doing my best too... (twice as much as them). If you're not confident or think it'll be hard to complete, shouldn't you just not log in? Otherwise, they won't be able to complete it either... I think people should refrain from logging in carelessly without responsibility... Am I being too sensitive? I'm angry and annoyed, So I'm asking for others' opinions...