A lot of the shill marketing is very hard to prove. A lot of the dialogue gets mixed in with commentors that have genuine brand loyalty.
It’s far too easy for a marketing team to acquire a high karma account and blend in. We’ll never get a truly clear picture of how much Reddit is astroturfed.
And to add, they will only fight if they have an unfair advantage (more people, better weapons, etc). It’s better to defend your own ground if necessary.