I have a Bachelor's degree in Philosophy and I found myself loving Russell and Mill because there's no pompousness to their writing. A lot of philosophers use very flowery language that's hard to parse, but Russell just gets straight to the point, clear as day.
In my opinion, philosophy should be written clearly so anyone can understand it (looking at you, Heidegger)

It’s dated, and ancient compared to the shit we spew, but it soo pure and clear (when you get the ear for it).

I am not a scholar, I can’t analyse prose or poetry, but his writing is cleansing and lights up the brain - especially if you have a fetish for reasonableness.

I know exactly what you mean and I've never quite had the words to describe this type of writing. It's definitely old fashioned to our eyes, but it's so dense with meaning. I felt the same reading some of the landmark SCOTUS decisions of the Warren court during the civil rights era.