And while you or I might be willing to put up with that as we're aware of the person and circumstances, there are many more people who don't know who he is and his circumstances and merely see the profanity-laden ramblings, and will simply leave. Keeping Terry on HN was untenable.
I feel bad for Terry, because by all indications those posts were driven by mental health issues rather than intentional bigotry, but the effect of allowing them in the community is the same.