Conceptually, I'd be inclined to have a method (call it 'acceptChanges') which could be invoked before you generate the HTML output. But I don't think we have that yet. And the downside is from an efficiency point of view, it would be an additional traversal of the document.
The XSLT in package org.docx4j.convert.out.html contains:
Using xml Syntax Highlighting
/*element styles*/ .del
{text-decoration:line-through;color:red;}
<xsl:choose>
<xsl:when test="/w:document/w:settings/w:trackRevisions">
.ins {text-decoration:none;background:#c0ffc0;padding:1px;}
</xsl:when>
<xsl:otherwise>
.ins {text-decoration:none;background:#c0ffc0;padding:1px;}
</xsl:otherwise>
</xsl:choose>
<xsl:template match="w:ins">
<span class="ins">
<xsl:apply-templates/>
</span>
</xsl:template>
<xsl:template match="w:del">
<xsl:apply-templates/>
</xsl:template>
<xsl:template match="w:delText">
<span class="del">
<xsl:apply-templates/>
</span>
</xsl:template>
Parsed in 0.001 seconds, using
GeSHi 1.0.8.4
so an expdient approach would be to alter the CSS definitions, or change these templates.