Google takes easily 48 hours to remove any black list.
That's correct, but some anti-virus software will still recognize things as malware if they haven't been updated, even if Google (or anyone) has taken that particular site off the blacklist.
I suppose there's nothing you can really do about that, other than replacing all instances of the URL (ex. images that are being posted on here, probably certain icons others are using) with a "..." and essentially rid the forums of the blacklisted link, but it doesn't seem like very many are having this problem anyway. As long as they realize there's no threat, and if they update their AV (or disable it from running constantly while browsing), they should be good.