Guy blocked me

Hey yall,
I was talking to this guy romantically for some time and one night we had an argument when I said I wasn’t really ready for a relationship, but he obviously felt the same and was annoyed I presumed he wanted to get with me.
Anyway he ended up blocking me on Snapchat but not on Facebook. Here he messaged me after I apologised and said ‘surprised you haven’t blocked me yet on here’.
Why would he block me on one thing but keep me on the other! I messaged him on Facebook but he always ignores it, like doesn’t even read it.