Lots of people do, and it makes no sense.

How do you pronounce “J”?

How do you pronounce “son”?

Now put them together.

LOL! I wouldn’t pronounce “J son” like Jason, either!

“Son” is pronounced “sun”. Jason is pronounced Jay-sin.

“Jay-sahn” makes sense because it’s how I pronounce it. Also, I’ve had coworkers named Jason, and I want to be able to say “Use JSON” without it sounding like I’m saying “Use Jason”.