Personally I don't mind the front page as it is (it's just a stupid default, who cares), but I can see why someone may have a philosophical objection to it. I can also understand the reasons for keeping the "default" front page somewhat filtered and sanitized.
Here's an alternative proposal: no front page at all.
Instead of a single front page, why not take some inspiration from 8chan's approach? The homepage could list all the spaces--perhaps with different views based on recent activity and number of followers--with links to both the "all" view and the default "clean" space pinned to the top of the list. These two would be slightly highlighted to make it easier for new users to navigate.
Yes, 8ch has terrible UX, but that doesn't mean that NAB's implementation has to be so terrible. If presented well, this would better surface the spaces feature (which to me is where the real long-term value is) while still providing a gentle introduction to the site for new users.
Just a thought experiment...