I've noticed a ton of Show HN submissions in New recently are promptly flagged and killed. They don't appear to be obvious spam at first glance so what gives? Are bots doing this?

Many of them _are_ obvious spam: submitted from freshly created accounts, meaning that they're not HN users, promoting a paid service or product, and with an accompanying post that looks like an advertising blurb instead of written to show readers something interesting.

I noticed that the "Show" part is now often an afterthought and many more people just drop ads for their product.

slop, or worse, condoning slop (Slop images in a human written blog post, etc); only serves to confuse and muddle.

Obvious slop.