Also, webviews aren't just used for browsing. More often they are used for embedded UI. I don't see how an ad blocker could feasibly tell the difference between

Also, webviews aren't just used for browsing. More often they are used for embedded UI. I don't see how an ad blocker could feasibly tell the difference between a legitimate UI script and an ad within the context of a webview; to the extent it can, it's simply creating threat space which defeats the entire purpose of the tool in the first place. A webview can't, and in my personal view, shouldn't, be under the control of the user. It's a tool for the developer. If you want to be safe in navigating to your links, you should paste it into a program you trust.