Almost everyone responding to you has told you that asking "Who is this?" is rude and unprofessional. Because it is. You keep saying you don't want to ask permission. You can't get around it. Asking permission is the ROOT of polite interaction.

Sometimes, I don't want to say please or thank you to people I hate, but I do, because it's polite. Its just how it is. It's the reason we teach children "Say please and thank you." or if you've ever played the game "Mother May I?"

If you call yourself "professional" you MUST accept that you have to ask things. I don't care what you do privately but in a business setting, it is a requirement.

I'm sure you are a hard worker and a good person, but in this thing you are wrong. Stop arguing with everyone. I don't care how nice your tone or if I can hear the smile in your voice, some one saying "Who is this?" when I'm making a business call is off putting. It sounds rude. You can't just think of yourself, you have to think of the person you are speaking to. They don't know you, they don't know your phrasing is harmless. And should you get the wrong person, they will make a fuss about it.

And yes, people who do not identify themselves are annoying. Yes it can even be rudeness toward you. But, politeness and professionalism also require that you rise above other people's mistakes.

You asked for opinions and you got them. You clearly don't like them, but they are correct. You need to change your ways.