IANAL, TINLA. From my superficial understanding of this law, you may weigh different interests and make a judgement call as to what data to delete and what to

IANAL, TINLA. From my superficial understanding of this law, you may weigh different interests and make a judgement call as to what data to delete and what to keep. Other regulations may be a factor in this, but even lacking those, it could be argued that your community cannot function otherwise. You would need to document how you came to your decision and inform the requestor about it. Note that you must still try your best. For example, you may not need to keep their actual email address to keep blocking it; a salted hash should do.