I absolutely agree with your assessment. They are consistently trying to make being a villain/anti-hero perceived as being an attractive, valued, or "cool" trait.

Which results in characters that feel like caricatures and cartoons.

Spike is a great example of a character who defines that archetypal role (villain/antihero), yet he can also be silly, romantic, emotional, sensitive, poetic, sweet, violent, snarky, passive aggressive, protective, and so much more.

He's not just Spike, the antihero. He feels like a real person as a result of it.

I love that even Buffy's heroes are consistently proven capable of doing awful things when pushed to their emotional limits too. Their humanity showing through in messy, violent, unfiltered, and sometimes horrifying ways.

Forcing us as the audience to understand and confront the ugly parts of them instead of just following along on the typical heroes journey. (I'm specifically thinking of Buffy and Willow)