I think there's something in this. If someone didn't have the luxury of seeing Quinn's mask slip in the later episodes in an initial play-through and all they had to replay were her actions in, say, the first three, I can easily see why someone might have decided Quinn wasn't for them early on. A lot of the stronger dislike for the character you see on here seems to be directed at the Quinn of episodes 1-3, to my mind. That might be because some players haven't felt any desire to even play through her optional scenes in episodes 6 or 7, because they've already made up their minds about her.
For those of us who have seen the softer side of Quinn as part of an initial/early play-through it's definitely easier to warm up to the character more quickly, I think. Having said that I've also read a good number of posts from people who have changed their minds about her, from initial dislike, to liking her more. Very few (if any) seem to have moved in the opposite direction (liking her, to not liking her), which tells you something about the development arc of the character.
I will say this, I was indifferent to her ( played this on Steam release initially, so Ep4, then came back at Ep6) and viewed her as a standard 2D antagonist.
What made me like Quinn as a well told villain BUT made me hate her as a character are the stuff you can see in EP6 and EP7. Oh cool, you are not some cardboard cutout, you actually have a backstory that explains some stuff about you...
And yet you see no problem in slapping around your best (only?) friend, look for blackmail material to force girls into prostitution, justify the actions you take because the consequences of your earlier actions are coming back to haunt you, and your only tactic is to double down and triple down, even though you already fucked up over and over again?
So DPC did well in constructing her character, in my opinion.
But I'd not run with that "Oh you guys hate her because you had initial bad impressions, she's best girl otherwise" thought train.
Believe me, big reason why I switched over from indifference to outright Quinn hate ( as DPC intended, I'd suspect, through good storytelling) is the shit she pulled in last two episodes.
If the Bojack Horseman of the story comes to you and admits his own wrongdoings, but you just keep going full on with your wannabe Walter White antics without any of the actual skills to back it up, you fucked up girl.
