This used to bother me, but I've been giving them the benefit of the doubt and assuming they are used to working with remote people in all time zones and it's a

This used to bother me, but I've been giving them the benefit of the doubt and assuming they are used to working with remote people in all time zones and it's actually a check to see if I'm present. If I don't respond, they'll try someone else and get an answer faster. The calling analogy doesn't work because the person on the other side of the phone had to pick up and is present. The "hello" is more like leaving a voicemail saying "If you're there, pick up, but you don't need to call back".