People have many different reasons for choosing to ride a motorcycle without a helmet. Some of them think that the helmets do not make that much of a difference, so they choose not to wear them. Others do not like the weight or complain about how they feel the helmets restrict their vision.
A crosswalk may give you the right of way. It may give you some protection in the sense that it alerts drivers that pedestrians may cross the road at that point. But it does not protect you at all when those drivers make a mistake. This is why it's so important to know what steps you can take to keep yourself safe.