I just checked and the site seems to be working just fine at my end, and if the problem yet exists then you’ll can try checking it via a VPN. Also error 522 is not always because of ddos attack and in this particular case it’s an cloudflare error, and it’s pertinent to note that I’m assuming that Freebitco is using cloudflare as their cdn. Lastly I’m pretty sure that Freebitco is spending lots of money on their security, and that’s why I don’t think they’ll ever get hacked.
More information on error 522:
https://support.cloudflare.com/hc/en-us/articles/115003011431-Troubleshooting-Cloudflare-5XX-errorsYes, they use CloudFlare because if it's inaccessible, the default CF error page is displayed.