Anti-fans
To be honest, ShinHye and JongSuk have anti-fans. Did you read that link I provided about fandom and anti-fans. I think that was a really good post written by a Korean. Anti-fans just spread "hates" whereas true fans will spread "loves". That's the different. No matter what, the anti-fans will always find something bad to say about JS or SH "just because". Do you waste time to reason with them? I will say, you can try but if the anti-fans are persistent, they will ignore your reasons so I will say just ignore those slandering/bashing remarks (i.e. don't waste your precious time on them) or just report them. But this world is made up of at least 80% good people so there is still hope in this world. We can only pity and pray for goodness from those senseless people, because they are missing out knowing what love & happiness is.
Sorry if my post offend anyone reading this. It's just my perspective so you either share them or don't because we are born different.