Others have pointed out the gist, but here’s my stab at it, with two of the full major quotes in one comment:

ep 1x12

I don’t really think there is a deep down. I think we are just the things we do.

ep 5x12

There’s no such thing as “bad guys” or “good guys”. We’re all just… guys, who do good stuff sometimes and bad stuff sometimes. And all we can do is try to do less bad stuff and more good stuff, but you’re never going to be good because you’re not bad.

These are both Diane, each time succinctly nailing my personal philosophy. Binary good person / bad person is a TRAP. After 76 episodes, BoJack never seems to learn this, often hitting one of two invisible, confusing barriers depending on circumstance or his mood:

1. If I do bad things, I can’t be good, so why bother?
2. If I’m good, I can’t do bad things, so why are you angry with me?

This confusion stunted his growth for decades. He’s fictional, but this disconnect in our own self-perceptions is commonplace, and so destructive to our growth too that its impact cannot be overstated.

So yes, it is missing the point to say he’s a well-depicted “bad person”. He’s a guy who does a loooot of bad things. He isn’t a bad guy – therefore, he can and should be expected to change and do more good things.