At the point that others get involved in attacking the officer... Yep, that was bad, really bad. There was even a kick to the officer's head when has was down.
I guess the cop was patrolling alone, with no partner. They're gonna have to reevaluate that policy.
A lot of departments patrol alone, due to manpower constraints and other considerations. When an officer observes an offense or a wanted suspect, he often has to act alone, not anticipating any escalation of resistance. Otherwise, they would be procedureally paralyzed.
We can't fall into the trap of blaming an officer or a department when thugs attack them alone. The blame fully falls on the scumbags.