Think of a single-core processor executing instructions one at a time. Now think of ten billion neurons in your brain out of which a large proportion is active at any time. That is definitely massively parallel.
This is like pointing to the billions of transistors in a typical modern CPU and claiming it is massively parallel despite being single core.
For many things the brain clearly can do multiple things in parallel (I can write one thing while talking about something else, for example). But it most certainly can't usually carry out many high level tasks at the same time.
When it comes to things like recognising words/symbols the question is how high level that actually is, and whether or not the brain has capacity for recognising more than one at the same time, and if so how many.