I actually find it quite readable - YMMV.
There's people reading this blog with all types of devices, screens, lighting and range of visual acuity. Even if you're blessed with perfect vision and excellent displays, it should be obvious that readability has been lowered for no obvious reason.
The point of a blog is for people to read it, so it fails at its foremost job.
Bringing the brightness levels of the background and text closer together doesn’t ever seem to work, but being able to add a slight blurry dropshadow behind behind each character might be a way to reduce the artifacts OLEDs seem to create when my eyes are tired.