"Link aggregator" is more appropriate than news aggregator.

I think of both as "ranked-threaded discussion" because I basically have no interest in their capacity as link aggregators, and rarely interact with link posts.

It's no more or less a news aggregator than Facebook. You may find something relating to news on lemmy but you're just as likely to find a drawing of a couple furries fisting each other.

I consider the site an online community where anyone can participate in or create a category to discuss anything under the sun.

social news site seems to fit pretty well

They are user forums/social media.

News Aggregator is only accurate if the sites actually scrape the web for news. Here and the other place rely almost entirely on users and bots for content. Since users and bots are neither hired or employed by the sites it's disingenuous to claim either generates anything at all. Neither site is relevant without the user generated content.