Nah. If you want to be outraged at Google, at least be correct.
This has to do with Google "collections", not synced bookmarks. Afaik, collections are a thing you only access on mobile through the google app, this doesn't even have anything to do with Chrome.
If you run chrome on mobile, for example, you don't have access to the collections. It's only through the google app.
Almost certain they monitor collections because they can be shared with public.