Does having a JD or PhD?

Not condescending, but the additional level of education does usually include not only more facts, but different ways of thinking and expressing oneself rationally in order to draw a conclusion.

The issue you describe is really just a rhetorical device regardless of education, not so much different then the teen girl saying "whatever" to get her point across.

Not everyone is skilled at all such techniques, but additional education does expose you to some advanced ones, and to those not familiar with that type of discussion, it could come across as condescending I suppose.

OTOH, the refusal to participate in some types of discussion, as wit the "whatever" girl, can be pretty condescending also.

Better to understand what rhetoric someone is using, and when and why that might be an appropriate choice. If you recognize it even if you don't understand it, at least you can ask nicely to steer the point in a way you do get. That would be a great conversational skill for everyone to have :)

There is no legal right to be condescending and anyone can be condescending if they want to.

Having a JD or PhD does make it more difficult to deal with uneducated people - sometimes frustration can come across as being condescending.

Either way, it is wrong to be condescending to others.