I think the reason PD's case stands out is that she's supposed to be the big good. The series paraded Rose Quartz as some practical goddess of the Crystal Gems, the infallible hero that "won" at a great cost and then sacrificed her life so Steven could live. Then, compared to the other Diamonds having all of their horrible atrocities mostly off-screened or solved before they became too much of a problem for everyone, Rose/Pink's actions and decisions were not only spelled out extensively with an in-depth look by both audience and cast, but also heavily criticized. Characters had breakdowns, the cast were fucking horrified, and while the other Diamonds were the catalysts, Pink was the root cause of everyone being wrapped up in a war they only "won" because the enemy figured no one survived, and thousands of years of conflict, issues and problems.
That's not to say PD is evil, by any means, but it does highlight why it's so easy to hate her in comparison: we have tangible and sizeable amounts of the consequences of her actions laid before us that are more visibly catastrophic than what the actual villains managed to accomplish, Cluster aside.