Honestly, by this point I'm less annoyed with the spam users, and more annoyed with your lack of action in preventing this.
Yes, the spam posts are very irritating, but honestly, they're not going to stop just because you swarm the boards with mods asking them nicely. They're probably bots in the first place, and they're probably earning revenues just by boosting the traffic on the site through the accidental click-throughs. There's no reason for them to stop.
It's not that much work to fix this problem on your side. A few regular expressions to process the post input should do it. It's not that complicated. I think it's about time you start restricting what kind of code someone can insert into a post.

Re: Open letter to The Nest
co-signed,
me
the gender reveal thread is spammed now, too. Super annoying...