My guess would be it's potentially a reference to someone with a disability, but that's a big stretch.
I'm also high level worker in that field, so I'm super sensitive to certain terms. "Spaz" doesn't trigger me.
Without looking it up, I'd describe a "spaz" as someone who moves and acts erratically.
That seems harmless.
And I HATE Tom Brady with the passion of a thousand blazing suns.
Edit: I looked it up. Interesting:
The word “spaz” is a shortened form of the medical term “spastic”. The earliest known use of the verb “spaz” was in the 1930s, and the earliest known use of the noun “spaz” was in the 1950s. The term “spaz” has evolved from a derogatory description of people with disabilities to a casual word for clumsiness or otherness.
The term “spastic” comes from the Greek words spasticos and spaon, which mean “to draw out” or “stretch”. The term “spasm” was already in use by Hippocrates to describe an epileptic fit. The term “spasticity” is used to describe abnormal muscle tightness due to prolonged muscle contraction. It is a symptom associated with damage to the brain, spinal cord, or motor nerves.
The term “spastic” was dropped by a major professional society that focused on cerebral palsy (CP) in 1994. This was in recognition that the term “spastic” had been co-opted by some in the lay public and applied as a derogatory term meant to bully.