Which technically speaking makes sense as those are Google-stored data referencing illegal data. You can't store actual ripped movies in Google drive either. Just no browser has decided to pull the trigger on this policy before since it's so much work to collect this data unless you're an actual web browser company as well. (So I guess this might be coming to Edge in the future)
Google literally crawls the web and serves piracy pages as search results, complete with keywords and all. How hard is it to just... Leave personal bookmark data alone? Encrypt it for the user and let it be? What the hell does Google have to be moderating personal saved links for?