I think timing is important, if BoJack reached out when Herb was first alone and needed someone then yeah I think Herb would have forgiven him. But the longer BoJack left it, the harder it was for Herb to accept an apology. And after a decade it was just never gonna happen.
BoJack is rude to everyone, a lot of the time. Including Hollyhock. He isn’t owed politeness and the things he did are not acceptable. He knew why she was distancing herself from him, he just didn’t know the exact reason.