Or, it's just busy :) I think the software in general have problems with long/deeply nested comment chains so maybe having a few of those being popular is enough to bring things to a halt.
By the way, you can usually work around performance issues on HN by either logging out (removing cookies if it doesn't load) or using incognito mode/private window (being logged out) as then the software can just serve cache views instead of having to fetch data on each navigation.
Edit: from the almighty dang:
> I've moved that one off the front page, partly because these are more or less the same story, but mostly because the traffic on this is boiling our poor server and I need to resort to tricks. Sorry all!
From "Twitter Suspends PG's Account" - https://news.ycombinator.com/item?id=34044525
Seems Elon Musk/Twitter is the one to blame for HN being slow right now.
"[...] but mostly because the traffic on this is boiling our poor server and I need to resort to tricks. Sorry all!"
The server IIRC does a decent amount of work per page determining your user-id and various behaviors of the text. But if you're a default, anonymous, "private" browser, the webpage is always more responsive.
Not necessarily "as responsive as it should be" mind you, but it does seem to help.