As I indicated, obviously it is the case. But there are also the other safety checks and other steps in the process that simply don't apply when you go to vote in person.
When you go to vote in person you don't have to fill out an application form. They don't have many days over which to review the material, cross-check it, to scrutinize it at the level of the returning officer's office. Rather, it's done just simply—when you're voting in person you only have the DROs and the poll clerks, rather than the returning officer's officials, and you don't have that time available. You don't have to provide your birthdate and that other information when you show up at a polling station.
So while it's correct that official identification isn't provided, there are other significant measures of protection that are in place by virtue of time and process and the application form, and the information that's required from you.