Aren't patent trolls called trolls because they litigate on broad patents, for which prior art exists in many case? If so, they can't protect a startup in any w

Aren't patent trolls called trolls because they litigate on broad patents, for which prior art exists in many case? If so, they can't protect a startup in any way unless you create broad and invalid patents. Your IP assets can be used to litigate by companies that aren't patent trolls.