The very first thing that most iPhone and iPad users do after opening a new tab in Safari is tap on the URL bar at the top of the interface to begin entering a new website URL or search query. With that in mind, wouldn’t it make perfect sense if the keyboard popped up automatically upon launching a new tab?
If you answered yes to that question, then I’d lean to agree with you. In fact, I find it rather odd that Apple hasn’t thought around the same lines.