Should I de-stake from a validator that is on the poor performers list?

This is a personal decision for every staker to make. The goal of this list is not to cause any validator to immediately lose stake, especially for transient issues that are corrected quickly by the operator. However, it is important that Solana validators are encouraged to maintain a reasonable level of performance, because the Solana network overall can only run as fast as those validators which implement it can run. Good performing validators are in essence "penalized" when low performing validators drag the overall performance of Solana down, and the reputation of Solana suffers.

For this reason, stakers should be encouraged to take seriously the appearance of their validator on this list.

However, immediately de-staking is probably not the correct course of action. A staker should first contact their validator and ask about their presence on this list. Establish a dialogue, get to know your validator, find out what the reasons might be, and give them a chance to correct the situation before de-staking.

But if your validator doesn't even have contact details - well then all bets are off. Probably should just de-stake a validator who not only has poor performance but doesn't even have a way to receive feedback about the issue.