Earlier quoted context omitted.
The insecurity relates the problem with allowing random usb devices to be plugged into a computer. Specifically, it points out that, even if you wipe an usb stick, you still can't trust that it's safe. The devices that Google is referring to should be inherently safe. If you don't trust the supplier of these devices then yes, that's an issue. But, in theory, you receive these from a trusted source. As long as the dev…
I have a Yubikey and it isn't read only. You can customize how it works with software they provide.
There was also a blog post by yubico confirming that the badusb attack is irrelevant on yubikeys. https://www.yubico.com/2014/08/yubikey-badusb/
I think the take away is that all the devices are read only except the Neo and the Device Firmware Upgrade (DFU) implementation on the Neo "requires the new firmware image to be signed by [yubico]. Yubico does not endorse nor support use of DFU for users"
The Neo also has javacard capability that lets you load applets. In the latest devices unless you purchase the developer editions, the javacard apps cannot be updated.* Older Neo's allowed you to build and load your own javacard apps.
* I'm not entirely sure about whether in the latest Neos the javacard apps can be updated to new official signed yubikey versions or whether the javacard apps cannot be updated at all...