You may not be able to stop desparate people from stealing, but if kids are repeatedly stealing cars for entertainment, then problem isn't the security of the cars.
The United States is an exception to the rule being the only first world country that I know of to not mandate engine immobilizers (I'm sure someone will be able to point an exception, but overall these are mandatory in a lot of countries for decades already).
You need to access the vehicle (if you are good by opening the door with a lockpick or with some other non-damaging trick, otherwise breaking a window), then you force the ignition block, removing the lock cylinder, then you use something to turn the ignition on.
In the '80's you would have probably used a screwdriver, as what remained below the removed lock cylinder would have been a slot, on these particular models you could use a pair of thin nosed pliers but a USB A connector is coincidentally just the right size for the "tab" that has to be turned.