Many idolize her purely for aesthetic reasons (ie her beauty and style), but many also idolize her for persevering and creating a remarkable career for herself despite the many abuses and personal problems she suffered.

Like this person said she was more intelligent and proactive than she's given credit for. She wasn't a piece of clay that was molded into the Marilyn Monroe we know, she was a hard-working businesswoman who developed a persona that had mass appeal and had the talent to back it up. It takes an incredible amount of resilience and strength to accomplish that despite the aforementioned abuse and addiction, and there's plenty to admire or idolize in her personal character even if you put her appearance aside.