Sure. Its definitely not ideal for the bike owners, but that doesn't mean it should be outlawed. There are many reasons this would be legit information to have and possess, and not all of them are nefarious in nature. Using your logic, should we also restrict websites that track campaign donations, just becuase the campaigners find it painful to their process?
The assembly of information is rarely a bad thing. Theft of said bikes is the 'bad thing'. Punish the people stealing, not the people creating maps.
Plus many organizations, including many governments, perform equally line-skirting things when collecting credit data, purchasing information, and private information. At least if it is public, you could see that your bike is known to be unlocked, so you could do something about it.
The pirate bay is seen/treated differently than all other user-content-generated sites, but it shouldnt be. Fair is fair.