I've noticed a similar tend when searching for specific ideas and phrases (even ones that are not JW specific)
I have also found evidence of their SEO tactics when the whole Russia thing was happening. Yes they are paying services to get then listed first, even using black hat methodologies (like articles in online African news papers and lots of other funny places that link back to their Russia articles on jw-dot-org)
I also use incognito mode, which basically keeps Google from knowing "who" you are, or associating your long term browsing history with your current session. One thing especially for mobile users to remember though is that your cookies (tracking) is still there until you close the browser so if you just got done binge reading on the jw site, your next search on a scriptural topic may still show the jw site at the top of the Google results, if you have not closed the browser first.
It also helps their online authority when sites like this have a massive amount of links to various jw org pages which is why I try to make sure not to type the jw . org site here because it tends to auto-link on this forum.
But yes, OP is absolutely right about the shenanigans, even if they are a little off, since they are not actually paying Google.
The link below (moz.com) is long but it shows you some of the nonsense links the bORG has acquired, including to online newswires and other places that are only for ranking higher.