> My timezone has not changed, my IP address and rough location has not changed, my screensize has not changed, my broadband speed has not changed, and my general computer dexterity has not changed, yet I am relentlessly targeted. On chrome I never saw these challenges, but on firefox with the privacy plug-ins I am always always always challenged.

That's because Google isn't just profiling "Tor users". They're going after anyone who values privacy in any way or technology.

Simply put, you're being punished for ensuring privacy. And anybody who uses Google's captcha services is an accessory to that.