Blogger comment form on home page, Intense Debate on post page - why?

Since nobody seems to care, I'll try and give you a hand. I gave it a quick look. It seems you have a blogger account. There must be something wrong with your template (the section dealing with the "Post a comment" link. Here's how to fix it by hand.

Go to 'Layout', choose 'Edit HTML'
Then search for the "post-comment-link" keyword

You should get to a section looking as follows:

<span class='post-comment-link'>
<b:if cond='data:blog.pageType != "item"'>
<b:if cond='data:post.allowComments'>

<a class='comment-link' expr:href='data:post.addCommentUrl' expr:onclick='data:post.addCommentOnclick'><b:if cond='data:post.numComments == 1'>1 <data:top.commentLabel/><b:else/><data:post.numComments/> <data:top.commentLabelPlural/></b:if></a>

</b:if>
</b:if>
</span>

What you need to do is replace the central block starting with "<a class='comment-link'" and ending with </a>
with the conditional block enclosed in between <!--Intense Debate--> comments in the following snippet:

<span class='post-comment-link'>
<b:if cond='data:blog.pageType != "item"'>
<b:if cond='data:post.allowComments'>

<!--Intense Debate-->
<b:if cond='data:post.numComments == 0'>
<div expr:id='"IDCommentPostInfoTitle"+data:post.id' style='display:none'><data:post.title/></div>
<div expr:id='"IDCommentPostInfoTime"+data:post.id' style='display:none'><data:post.timestampISO8601/></div><div expr:id='"IDCommentPostInfoAuthor"+data:post.id' style='display:none'><data:post.author/></div><div expr:id='"IDCommentPostInfoCats"+data:post.id' style='display:none'><b:if cond='data:post.labels'><b:loop values='data:post.labels' var='label'><data:label.name/>|</b:loop></b:if></div> <a class='IDCommentsReplace' expr:href='data:post.url' expr:name='data:post.id'>Comments</a>
<b:else/>
<a class='comment-link' expr:href='data:post.addCommentUrl' expr:onclick='data:post.addCommentOnclick'><b:if cond='data:post.numComments == 1'>1 <data:top.commentLabel/><b:else/><data:post.numComments/> <data:top.commentLabelPlural/></b:if></a>
</b:if>
<!--/Intense Debate-->

</b:if>
</b:if>
</span>

Hope this helps.