Thank you … some progress. The icon is now visible on all pages. The only mystery is why I needed to explicitly make it visible on the laptop when everywhere else it is visible by default. But …
When the icon first appeared it said 341 blocked, but the ads still showed. I refreshed the page and the ad in the top block disappeared and was replaced by the word Advertisement … for 10 or 15 seconds and then the ad showed up again. When first refreshed the count of ads was in the 60 but then gradually climbs into the hundreds. Scrolling a bit farther down the page there is a gray box with the word Advertisement in it … for a few seconds and then the ad appears. On a subpage, the ads in the right column appear right away and the ones between stories appear after one scrolls that far on the page.
Maybe a different ad blocker?