Where does it say it was a felony stop?
FBI press release (excerpted)
At approximately 4:25 p.m. (PST) on Tuesday, January 26, 2016, the Federal Bureau of Investigation (FBI) and Oregon State Police (OSP) began an enforcement action to bring into custody a number of individuals associated with the armed occupation of the Malheur National Wildlife Refuge...
All of the named defendants face a federal felony charge of conspiracy to impede officers of the United States from discharging their official duties through the use of force, intimidation, or threats, in violation of Title 18, United States Code, Section 372.