Concern troll

A concern troll is a person who participates in a debate posing as an actual or potential ally who simply has some "concerns" before they will ally themselves with a cause. In reality they are a critic. And they use those concerns in an attempt to undermine the conversation. Concern trolling is primarily used to inject the oppositions talking points into the conversation without erasing suspicion..

An example would be:

Democrat enters republican chat:

Democrat: "hi guys a hillary supporter but trump is a racist"

This strategy would leave the troll met with extreme opposition and potential Banning

However if instead:

Democrat: "hi guys im a trump supporter but his recent racist remarls are concern"

This is much more sneaky and would result in an actual discussion

Concern trolling can result in continual reversion to discussions in attempts to appease the troll's concerns, frustrating attempts at more serious discussion. Concern trolls are not always self-aware; they may also view themselves as potential allies who have just, oddly, never met a conservativ opinion they liked.