“1x1” mainly talks about how humanity feel guilty remembering that they destroyed other species or even other people because of ethinical, religious, gender and sexuality differences.
[The song addresses] the guilt that we as a society carry for what we’ve done to other species and ethnicities and other genders.
Just like “Teardrops,” the song can be related with Oli Sykes problems with addiction in the past. Quarantine could have brought back these dark memories and it shows him feeling guilty about it.