Here's a run down of everything that's happened so far from the perspective of an Eunhyuk fan. Us fans are not saying that IU should get hate instead of him but rather asking why Eunhyuk should still be getting hate to this day.
We woke up one day to news of IU releasing a picture with Eunhyuk on her public Twitter account, and public sentiment grew heated. Everyone knew that it wasn't just a simple selca and all sorts of rumors spread out from IU being pregnant to other dirty things. Still, SuJu fans shielded IU knowing that people were being too harsh to a young female singer.
According to IU on broadcast, Eunhyuk had called IU to ask if she was okay but what Eunhyuk and his fans got in return was Loen putting out a clarification saying he was visiting the sick, which SM was not informed of at all.
Eunhyuk did not upload the picture, nor did he give that clarification himself (he's the victim in this, no reason for him to even clarify it). Ever since then, all posts regarding Eunhyuk were filled with immense hatred. Despite the situation, Eunhyuk had to go through with all of the broadcasts he had scheduled.
This is an account of 'Star King', which he recorded immediately after the scandal: (Account of someone at 'Star King' recording basically listing all of the sexually suggestive comments the panelists made at him alluding to his scandal with IU like "Should we turn on 'Good Day' for your dance segment?" and when a contestant brought a bed as a prop, panelists were like "Oh Eunhyuk knows all there is about beds, yeah?")
Despite being the victim, he had to listen to all sorts of these comments and laugh them off. Panelists did not hesitate on making sexually suggestive comments and laughing at Eunhyuk's face but when IU was on the show, they'd look at her with upset expressions as if they felt bad for her. Eunhyuk eventually ended up cutting back on his active TV schedules.
Then a few days later, IU uploaded a post on her fancafe skimming over the issue and talking about how she was sorry she worried her fans while she was at home gaining weight. Then she went on the 'Hwashin' talk show and only clarified rumors like her pregnancy rumors by beating around the bush and revealing that Eunhyuk had called to her to check if she was okay. Much to the dismay of Super Junior fans, she did not apologize for the scandal at all.
While we agree that IU suffered hateful comments as well, she never once properly apologized to Eunhyuk or Super Junior fans when they're the ones who were unfairly suffering because of her mistake. Eunhyuk did nothin wrong but had to deal with 'visiting the sick' comments on 'Radio Star', comments which were never directly said to IU when she was on TV. Eunhyuk was the clear victim but he was the one being dealt all the pain.
There are tons of private relationships in the entertainment industry but it was IU who released the information to the public, whether it was on purpose or an accident. Eunhyuk was literally asleep and woke up to this entire scandal by no fault of his own. He is still suffering from dirty comments to this day that of course his fans are upset over.
Super Junior fans are scared even when Eunhyuk gets in the news for positive things. It wasn't until this year that fans felt comfortable going in to read the comments.