Patreon have started using this type of captcha on several of their pages, and previous experience shows that it can be a real pain, asking questions to which there is no clear answer, and sometimes getting stuck in an endless loop.
Not that they're the only site doing this, but hey, if it drives patrons away that's gotta be bad.
Have had experience with this before, and done a few tests on why it gives some people a world of pain, but not others.
The lowdown is the reverse of what Google says. It isn't a question of having browser plugins or extensions. It's if you have a 'clean' browser that you will be in for trouble.
What this thing does, is that it looks for cookies on your computer that have tracked your visits to previous sites using Google Adwords or Adsense. If it finds enough of this crud on your computer, it assumes you're not a robot. So, it's if you maintain your computer in a spick 'n span condition with no junk buildup, then you will get hell from the captcha. Or, likewise if you use a browser with a privacy mode.
Occurs to me that a robot operator could simulate this cookie infestation situation anyway, so it probably isn't a very effective protection.
The other reprehensible thing is that following the reCaptcha troubleshooting instructions will result in people ripping out plugins and so on, needlessly causing themselves all sorts of computer trouble. When the real issue is a clean browser with no old data. Or, privacy mode on.
Also just discovered that if you update your browser, the thing then demands that you 're-validate' your account by responding to an email. Imagine if every site started doing this. It would mean everyone having to stay with old and potentially vulnerable browser versions, because updating or patching would mean a world of pain. Would that be good for security? I somehow don't think so.