Hate speech is clearly defined in various laws against the concept. So it’s not really up to taste. Most popular services attempt to remove hate speech, but doesn’t look like KF does.

Btw, a forum dedicated to the principle and culture of free speech would absolutely (by definition) be promoting/hosting hate speech.

Most laws on hate speech don't use the term hate speech.

What is your personal understanding of the term?

Does it matter? That's up to the people hosting the content right?

I'm not sure I understand your last sentence? If I were running a forum dedicated to the principle/culture of "free speech" I would think it's especially important to avoid promoting hate speech, or you run the risk that free speech and hate speech become seen as synonymous, and the wider public deciding that free speech isn't a worthy ideal after all.

I ended up conflating hosting and promoting which wasn't clear enough. You would be definitely be hosting hate speech, which is essentially promoting it (by using the internet to make that speech more accessible to others than it would be otherwise).

The alternative is to accept that moderation is NECESSARY for online communities (or else spam and hate speech will take up a huge part of the content and suddenly you'll realize you're essentially promoting this content afterall) and moderation will always look like the opposite of "free speech".