Yeah I understand it can seem scary. But like darthmongoose said, it's included because there can be a lot of overlap of pitch ideas. Since pitches tend to be just the starting point of a creation, one might think it's a super unique idea, but they may not be aware that many others may have made something similar or even identical as a premise.
That said, they never own your particular pitch, so you're still free to develop your ideas as you see fit if the pitch isn't chosen.
And personally, I think that even if a creator starts with an identical premise as something else, they'll inevitably write a unique story if they remain honest with themselves and express through narrative what they believe. Cause each person's perspective is unique.
