Why am I receiving a capcha when I visit this site?

My PCs all use Linux OS and they have no spyware. I started receiving it not just here but on other sites as well.

Maybe my network connection is compromised?

Are you using some proxy, Tor, etc?
CloudFlare security has been very sensitive and annoying in these last days. By the way, the captcha is very difficult to solve.

I don’t use any proxy but I do use a Torrent client. My use of Torrent client might be the reason triggering this.