"1385. Use of Army and Air Force as posse comitatus
Whoever, except in cases and under circumstances expressly authorized by the Constitution or Act of Congress, willfully uses any part of the Army or the Air Force as a posse comitatus or otherwise to execute the laws shall be fined under this title or imprisoned not more than two years, or both. "
See Bolded part, does not apply here.
If it walks like a duck & quacks like a duck...
While it may not BE the army if they dress like them & use the same tactics then what is the functional difference.
I think his point still stands.