Docker images not shipping with defusedxml

Moving the thread here.

I am running diffoscope 294 over two XML files (attached as txt files reference.txt rebuild.txt). I get a diff using XXD instead of plain text diff because of the following error message:

2025-04-21 13:51:26 W: diffoscope.comparators.xml: Vulnerable version of pyexpat detected; disabling comparison of XML documents. Install defusedxml or upgrade your pyexpat.

Note that this is not visible when output type is JSON.

However, when I install defusedxml, it works and gives a nice diff like below.

│ -          <description>Specifies the Proxy Configuration Controller Service to proxy network requests. If set, it supersedes proxy settings configured per component. Supported proxies: SOCKS + AuthN, HTTP + AuthN</description>
│ +          <description>Specifies the Proxy Configuration Controller Service to proxy network requests. If set, it supersedes proxy settings configured per component. Supported proxies: HTTP + AuthN, SOCKS + AuthN</description>

Is there a specific reason that defusedxml is not shipped with the docker image?