I have a Dell desk top computer.

I don't have a DU membership star.

I use AdBlock and I never see any ads.

I hope that helps.

you must be infected, run scans

I only know what I stated, You can try to ask admins directly - https://www.democraticunderground.com/?com=ata

They are running a version of Unix at the core, the original OS for hacker attacks.
Apples just happen to be far less popular than Windows PCs, so they get less hacker attention. But still some attention.

I have a membership and I still use ad blocker. I never see ads anywhere. It's great and I also use ghostery.

I use Apple desk top and phone and have no problem..A few years ago I let my Membership expire and I resubscribed. Seem to take a long time before it kicked in. Good luck.

Have you tried logging out, then logging in again? Every once in a while, I'm asked to log in anew, and before that happens, ads do appear; they disappear as soon as I re-log in. If none of this works, you'd better ask an administrator.

Was that Apple "upgrade" really from Apple?

Did you install some app that was supposed to "improve" your shopping or browsing experience?

Did you sideload some sketchy game?

Etc...

I noticed this too, about two weeks ago, there was an update, either a new OS, or else a major patch that was applied. Immediately, I noticed that anytime I scrolled past the video player, it would shunt into a PVP and keep scrolling down the screen with me, even if I paused it. You can stop it and shut the video window, but it’s an inconvenience because I you never had to in the past.

Around the same time, all of the ads I began seeing online took a decided turn for the extreme right wing reactionary. I doubt that’s related, it’s just that I’ve been forced to look at it now since the video player scrolls down the screen with me anymore.

Lots more ads. I had minimal ad blockers in place, the less on my hardware the better, it runs faster that way, but this update obviously was intended to defeat a lot of the blockers, so ick.