Imo, there's a time where a typekill is just uncalled for.
If turn around the corner, and you see someone that is typing a message (And was doing so before you found them), it's not nice to kill them.
However, if you're fighting someone, and they suddenly stop to chat, while you're still in combat, blow their friggen head off. The same goes for a person just walking away, and then they stop to chat.
Typekilling is rude under most circumstances. The easiest way to avoid getting typekilled is for everyone to stop asking such lengthy questions and demanding an answer beyond "Yes" or "No". If you wish to talk while fighting, use voice chat. Otherwise, you're just someone that's in the way.
Just answer questions once you're dead, or far away from everyone. If you ask someone a question in a DM, don't expect a hasty answer. That's like saying "Hey, drop your guard for a moment and pay attention to me because I'm asking a question that you've probably answered a hundred times, or the answer is blatantly obvious, and I'm also more important than the person trying to currently kill you."
When it comes to typekilling, there's two parties involved, and either one (or both) could be at fault.