The negative trust by these two seems pretty shady to me. I don't think there was any credible evidence of polo scamming in 2017.
Polo was way behind on their support tickets at the time. They also had taken down their trollbox at the same time. I can see where people were getting leery that another exit scam was looming. Polo has since changed ownership, anyway. So the tags should probably be revised. Unfortunately, Zepher can't revise his. 
It's not just about being behind on support tickets. Some people had withdrawals that were pending for months, causing them to lose a lot of money. Poloniex failed to respond to their tickets and never covered any of the damages caused by their lack of service.