Why enter the Baltic instead of attacking Wilhelmshaven?

If the fleet must face forts and mines, why not attack Wilhelmshaven directly?

Wilhelmshaven had Germany's strongest minefields and defenses, while the neutral Danish Straits were international waterways whose defenses might remain silent.

Wilhelmshaven and the Danish Straits presented very different barriers. Wilhelmshaven was a principal German naval base protected by dense minefields, forts, and the ships stationed there. The straits belonged to a neutral state and were treated as international waterways, giving Britain a chance to pass without fighting Danish batteries. That legal and diplomatic gamble could bypass the strongest part of Germany's coastal system. The Baltic route remained dangerous, but it offered surprise and an operational purpose that a frontal assault on Wilhelmshaven lacked.