<p>Consider some existing tags for <a href="https://stats.stackexchange.com/questions/tagged/python" class="post-tag" title="show questions tagged &#39;python&#39;" rel="tag">python</a> (1233) libraries:</p>

<ul>
<li><a href="https://stats.stackexchange.com/questions/tagged/scikit-learn" class="post-tag" title="show questions tagged &#39;scikit-learn&#39;" rel="tag">scikit-learn</a> (543)</li>
<li><a href="https://stats.stackexchange.com/questions/tagged/pandas" class="post-tag" title="show questions tagged &#39;pandas&#39;" rel="tag">pandas</a> (30)</li>
<li><a href="https://stats.stackexchange.com/questions/tagged/numpy" class="post-tag" title="show questions tagged &#39;numpy&#39;" rel="tag">numpy</a> (42)</li>
<li><a href="https://stats.stackexchange.com/questions/tagged/scipy" class="post-tag" title="show questions tagged &#39;scipy&#39;" rel="tag">scipy</a> (112)</li>
<li><a href="https://stats.stackexchange.com/questions/tagged/matplotlib" class="post-tag" title="show questions tagged &#39;matplotlib&#39;" rel="tag">matplotlib</a> (23)</li>
<li><a href="https://stats.stackexchange.com/questions/tagged/pymc" class="post-tag" title="show questions tagged &#39;pymc&#39;" rel="tag">pymc</a> (156)</li>
<li><a href="https://stats.stackexchange.com/questions/tagged/statsmodels" class="post-tag" title="show questions tagged &#39;statsmodels&#39;" rel="tag">statsmodels</a> (73)</li>
<li><a href="https://stats.stackexchange.com/questions/tagged/theano" class="post-tag" title="show questions tagged &#39;theano&#39;" rel="tag">theano</a> (44)</li>
<li><a href="https://stats.stackexchange.com/questions/tagged/tensorflow" class="post-tag" title="show questions tagged &#39;tensorflow&#39;" rel="tag">tensorflow</a> (112)</li>
</ul>

<p>There are several possible things we can do with them:</p>

<ol>
<li><p>Do nothing: leave all these tags alone.</p></li>
<li><p>Make all these tags synonyms of <a href="https://stats.stackexchange.com/questions/tagged/python" class="post-tag" title="show questions tagged &#39;python&#39;" rel="tag">python</a>. This is pretty radical, some of these tags are widely used.</p></li>
<li><p>Keep the tags about statistical libraries, but get rid of the tags about non-statistical libraries; that is what you are suggesting in your edit. However, I find it difficult to draw a line here. [scikit-learn] is clearly statistical. You say that [pandas] is not, but it is about data storage and manipulation which can be very pertinent to statistical analysis and on-topic; also, it includes some statistical processing routines. [matplotlib] appears entirely non-statistical, however it is about data visualization which is on-topic too.</p></li>
</ol>

<p><strong>Given these considerations, I am inclined to prefer approach #1.</strong></p>

<p>One thing we could do to address your concern about off-topic questions, is to add a cautionary note into tag excerpts warning people that programming questions are off-topic. E.g. [pandas] wiki excerpt currently reads</p>

<blockquote>
  <p>Python library for data manipulation, implementing R-style data frames. </p>
</blockquote>

<p>but we could add something like</p>

<blockquote>
  <p>Python library for data manipulation, implementing R-style data frames. Programming questions about Pandas are off-topic unless they have statistical content. </p>
</blockquote>
