Phone calls still assume the people on the receiving end are attached to a desk.
Why couldn't this call be an email? Why would you call, when you know that you are near indistinguishable from spam calls about Microsoft services and Nigerian princes?
Phone calls also assume the person on the other end wants to be bothered. If you choose to not answer, you're treated like the a-hole and are expected to explain why ("I've been trying to call you. Why haven't you picked up?")
"A telephone is a fantastically rude thing. I mean, it's like going 'speak to me now! Speak to me now! Speak to me now!'. If you went to someone's office and banged on their desk and said, 'I will make a noise until you speak to me' it would be considered unbelievably rude."
I have a coworker that if you try to call her and she doesn't want to talk she straight up changes her status to away or busy and then just ignores your call. She is an a-hole but not for this reason, lol.