atom syndication spec contradicts itself?

Am I right, or am I misunderstanding? I cant’ be the first to have ntoiced this.

4.1.1.1 ….It is advisable that each atom:entry element contain a non-empty atom:title element, a non-empty atom:content element when that element is present, and a non-empty atom:summary element when the entry contains no atom:content element. However, the absence of atom:summary is not an error, and Atom Processors MUST NOT fail to function correctly as a consequence of such an absence.

4.1.2 …atom:entry elements MUST contain an atom:summary element in either of the following cases:

• the atom:entry contains an atom:content that has a “src” attribute (and is thus empty).
• the atom:entry contains content that is encoded in Base64; i.e., the “type” attribute of atom:content is a MIME media type [MIMEREG], but is not an XML media type [RFC3023],

So which is it, summary is required when there’s no text or html content, or summary is just recommended but never required?

I hope just recommended, because I’m not sure I have a good summary available.