I don't mind the ads, they give me a sensation that I am "paying" for my content

Its the algorithm that seems to be nearly personified (not personalised

) and yet purposely dumb that made me notice it.
I guess those could be described as semi-relevant, as in my case. Unless you added a little sarcasm to the mix in the first phrase. It seems to mirror my situation exactly.
Quite a lot of my posts come flavored with sarcasm/snark these days. Call it a freight train's worth of frustration with RL issues going on that sometimes creeps into my non-news site/FB posts. But in the case of Dune-related ads, I assumed you meant that the ads were trying to sell you real spices - the kind you eat. If that's the case, then it's somewhat relevant, given that the Fremen and most aristocrats who could afford it would consume melange on a daily basis.
Its funny, but a lot of "inappropriate" adds are there to mark that you are not surfing in a "popular" part of the internet. Its not about selling ads for revenue, but rather to show that the ad providers do not approve of the contents of a site. Some of the more interesting places I know used to get these "inappropriate" ads. Also Russian internet in general in the 90's and early 2000's used to be the same. Thats my take on this based on 20+ years of surfing.
If Google doesn't like academic discussions of a novel that was published in 1965, it can take a hike. Arrakeen was a forum that was dedicated to Frank Herbert, his Dune novels, his non-Dune novels, and much more. That was the place where I found people who could explain
God Emperor of Dune to me - up until that time I found that novel an unbearably awful slog and didn't get most of what it was about.
As far as ads go... I accept them as a necessary evil on TV, though it does grate that I've never actually seen some shows on PBS when they weren't broken up by 10-15-minute pledge breaks. I had to buy the
Yanni: Live at the Acropolis video to see it in its unbroken form.
What solidified my loathing for ads, though, was some years ago when I found a YT channel where someone had uploaded several
years' worth of
General Hospital episodes. These were from years I'd missed when I didn't have a TV, and when I finally did get one and started watching again, I couldn't make heads or tails of the storyline and there were too many new characters. But when I found that YT channel, I was able to catch up on over 3 years' worth of episodes in about 3.5 months. When you remove the ads, that show is about 36 minutes long, rather than 60.