- Your ISP is a source of a lot of malicious traffic
- You have some browser extension or other adjustments that makes it harder to analyse you as a genuine web browser
For example, using a browser automation like Selenium testing triggers "hard" reCAPTCHA. Not sure if this because of some automated API that Selenium exposes, or just because your browser profile looks virgin (no cookies) without any prior reCAPTCHA solves.
Also my IP address rarely changes and I don't think that any malicious traffic is coming from it.
And I have Comcast, so I hope that they didn't blacklist all of us...
(I did talk bad about Google a few times though, maybe that's it)
If you're actually concerned about that kind of data leakage, you want NoScript, full stop.