I'm in a country that uses the 24 hour clock. We also say we meet at 4 or at 10, and are able to derive from context whether that means in the evening or in the morning.
We have Dinner at 6, not 18:00 (people would be frowning if you'd say 18:00 out loud there). In messages I think I'm one of the few that always says "16:15" because I just hate ambiguity. If context does not clarify enough people say "in the morning/afternoon/evening/night But (easily) arguably "context" is even worse than AM/PM! Though I can't remember this going wrong ever.
I remember as a kid looking at a digital clock and subtracting 2, then dropping the leading 1 to get a "feel" for the time. Nowadays I'm 24h native and don't like the ambiguity of 12 hr references.
I set al my clocks to 24 hr (unless they have arms).
So yeah, here we are, all cool with our "military time", ahum.