They KNOW they have been low-key harassing and insulting her for years now, but in their eyes it's just "Olicity swag", "throwing shade" and "having an opinion". So, they just brush off any criticism, even if people provide them with screen shots of tweets where THEY themselves are beyond any doubt shown to be mean to KC or anyone who dares to criticize their flawless GODDESS. They even ostracize and mock those of their own who don't comply to the dogmas of the cult, e.g. those who don't agree with the common practice of "trash shipping" Stephen and Emily and trashing mocking his wife, who they call all sorts of names, e.g. "Voldy" and "T-Mal". I've chatted with olicity fans who have left the fandom because they were bullied when they protested against the #stemily shipping. There is even a tumblr blog for the Olicity apostates:

https://failedthisfandom.tumblr.com/

Then these very same folks go on "Uncle Guggies" twitter, posing as the "good and respectful" and being all sanctimonious about "bad" and "hateful" Laurel stans, who are being so mean to poor old Guggenheim and his writers.

Of course not all Olicity fans behave like this, but many of those who are most active on social media and the producers/writers twitter timelines, and who complain about the bad behavior of the non-shippers belong to this group. One thing they don't seem to understand is that they really didn't have to pour vitriol over Laurel/NC or harass KC, because they were getting everything they wanted anyway. Laurel was marginalized in favor of Felicity, Felicity was raised to the skies by the "Arrow" writers (I've never seen as much character shilling in any show as I've seen other characters shill Felicity), Felicity become the main love interest. On the other hand, the non-shippers/LL fans have been constantly ignored and shat on by the producers, and the fridging of Laurel is just the culmination of this treatment. So, if the non-oliciter fandom is trashing Guggenheim et al right now, at least they have a reason to be pissed off.