I was bitten by this as well. My product retrieves RSS feeds from public government sites, and suddely I'm blocked by cloudflair's antibotting for tryng to access a page that was specifically created for machine consumption. It is not that the website owner or publisher intend to block this. They are unaware that turng on Cloudflare will block everything, even stuff allowed to be consumed according to robots.txt .
P.S. when I mentioned this here on HN a few weeks back, it was implied that I probably did not respect robots.txt ( I do, Cloudflair does not) or that I should get in touch with the site administrators (impossible to do in any reasonably effective way at scale).