Dog-piling is when someone expresses an opinion and people swarm in the comments telling the OC how wrong they are and how right they are. Typically the person getting dogpiled is downvoted into oblivion in the process. Note that I'm not talking about anything controversial in their opinion or the comment being trolling in any way; just any general disagreement with the groupthink.

Brief example:

User 1:  There are lots of factors at play here, not just money.  There's X, Y, Z, and those are all independent from money.
  |____> User 2: No, it's money.  It's always money
  |______>  User 4: Right?  How can anyone think it's anything *but* money?  Some people!
  |____> User 3: Yes, well, X, Y, and Z wouldn't be a problem if not for capitalism, so it's definitely money, and you're wrong.
  |____> User 5: It all boils down to money; always does.
  |____> User 6: Of course it's money.  Only a capitalist bootlicker would think otherwise.
  |____> User 7: Go back to Reddit, troll.
  |____> User 8: You're so close, but it's money.  
  ...
  |____> User 999: (Same as the last 998 comments; contributes nothing except attacking the opinion for being different)

None of that adds anything to the discussion; they're not engaging on the subject, just attacking the opinion because it differs.

That behavior does not seem healthy to me and seems like it's almost designed to discourage anyone from expressing any opinion that's not part of the established group think. Again, I am not talking about trolls here, just any kind of differing opinions.

Should that kind of behavior be discouraged? If so, as a mod, what would be the best way to address it? After the 2nd or 3rd dogpile comment, start removing subsequent ones that are just piling on?

It's definitely a people problem, so I'm curious what would be a gentle but firm way to deal with it.