Why pandoc keeps span and div tags when converting html to markdown?

I'm a pandoc newbie, so I must be missing something obvious. I'm trying to convert MS Word generated HTML file to markdown. Here is a test html:

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
  <title></title>
</head>
<body>
  <div class="Section1">
    <p class="Question"><span style="FONT-SIZE: 10pt">Today</span> <span style=
    "FONT-SIZE: 10pt">is</span> <span lang="HR" style=
    "FONT-SIZE: 10pt; mso-ansi-language: HR">a</span><span style=
    "FONT-SIZE: 10pt">nice</span> <span style="FONT-SIZE: 10pt">day</span> 
    </p>
  </div>
</body>
</html>

and I try to convert it with:

pandoc -f html -t markdown test.html -o test.md

I was expecting "Today is a nice day", but got:

<div class="Section1">

<span style="FONT-SIZE: 10pt">Today</span> <span
style="FONT-SIZE: 10pt">is</span> <span lang="HR"
style="FONT-SIZE: 10pt; mso-ansi-language: HR">a</span><span
style="FONT-SIZE: 10pt">nice</span> <span
style="FONT-SIZE: 10pt">day</span>

</div>

Why was the div kept? Why were the spans kept?