I said the same thing in another thread. It is ridiculous that they changed reader mode.
That ain't an Opera thing, I believe. It's web design. I experience this on my desktop on a different browser, so...
I believe OP is referring to the reader mode in Opera, not the webpages themselves. Opera used to load full articles in reader mode. All it would contain was the text and images from an article. Now it loads at most a sentence or two, maybe a picture, an ad and a button to take you to the full webpage. This is the exact opposite of what reader mode used to be. Like OP, I feel frustrated, annoyed and insulted.
First they injected ads into the newsfeed.
Then they add the "tap to read full article" button in reader mode.
Then they inject ads into the reader mode.
What's it going to be next?