Optical illusion
At first glance, this looks like a typical way to lock your bike up when you leave it to go inside a building. But then you see that it’s all wrong and it was nothing more than an optical illusion. Anyone could just push the handle through the hole completely and run off with the bike.
Judging by the style of the bike we assume it belongs to a younger person who really didn’t think this one through. Young people are often careless with their things, especially if they didn’t have to work to buy them, but they came from their parents. Maybe their parents should have taught them first about how to lock up a bike.