It has nothing to do with political affiliation. The difference isn't between their adult politics. If someone can't tell the difference between a 7 year old who looks in their baby sister's vagina to see if what mommy said about a uterus is true, and a fully pubertal 14 year old male repeatedly sneaking into his little sister's rooms or whatever, some as young as 5 ad 6, pulling down their pants and groping their private areas for sexual gratification, despite being "disciplined" for such conduct already, I can't help you.
In no way is what Dunham readily admitted to any form of child molesation or pedophilia. Including masturbating next to a sleeping, same sex sibling. The same cant be said for what Josh confessed. Sorry.
I'm not a fan of Dunham or her show. I hear she's always naked on it and the few clips I've seen she just annoys me. I also find her descriptions of these things in her book to be strange and purposefully trying to be shocking. I don't like her. If she had done what Josh had done to little children I would be disgusted. But she didn't. And frankly, despite being opposed to the patriarchal ideology of the Duggars, I like them as people, with the exception of the mom who seemed off. They are mostly sincere, nice people.
Finally, Bill Cosby is a liberal democrat. And I can't say what I think of that rapist for fear of getting in trouble. Suffice it to say that due to his age at times of offenses, his calculated methods, his lies about the victims, and the crushing number of his offenses, I find him to be much more reprehensible than a teenage offending Josh Duggar.
Nope. This ain't about politics. It's about sex abuse and hypocrisy and hiding behind the veil of celebrity.