Why do people comply with England’s honors system and always call knighted people ‘Sir’? I see it all the time with popular figures (e.g. Attenborough, Ferguson) on social media comments and I’m not from the UK.

You can also notice this in wikipedia. The page for a knighted person will always start with “Sir X is/was a …” even in languages other than English. The only exception I found to this was French wikipedia. I hope their journalists and general public do not comply with this idiotic nonsense as well.