The First Amendment and Kittens

The argument fails here.
An emblem of a thing is not the thing itself. The flag is not the nation or the body of law which comprises it.
To assert otherwise is to indulge in magical thinking which is generally considered to be irrational.
How malign or benign is flag burning? What is its value? In Texas v. Johnson (1989), the Supreme Court decides that the act of burning and spitting on the flag is valuable because by permitting it we honor the history and tradition the flag symbolizes: “We do not consecrate the flag by punishing its desecration, for in so doing we dilute the freedom that this cherished emblem represents.” Get it? We cherish the emblem by burning and spitting on it.

Be very cautious reading Stanley Fish. He is far too intelligent to make this argument in error or by accident.