Interesting article, though obviously slanted against federal officers. What the article didn't mention is that many county sheriffs, including Riverside County, are very satisfied with their cooperative agreements with BLM Law Enforcement, and have been quoted as stating they don't know what they would do without it.
San Bernardino County Sheriff Penrod revoked his department's longstanding cooperative agreement with BLM Law Enforcement about 3 years ago. I've been told the Fisher grazing controversy was not the real reason for this action, which may have had more to do with complaints against BLM Barstow's Chief Ranger.
While the authority of the County Sheriff is well established back to English law, the authority of federal officers on U.S. Government land is also well established, in the U.S. Constitution. The public benefits when these "badges" get together and cooperate for the greater good, rather than fighting their little turf wars.