They're pretty old. I remember when Google added an option to block domains (the option you want) around 2011 and they were the first thing I removed from my results, along with Wikipedia mirrors.
After the option to block domains was removed around 2014-2015, I rarely came across those anymore, but it seems they're back...
After the option to block domains was removed around 2014-2015, I rarely came across those anymore, but it seems they're back...