If I take you as you phrased it "need to say something" the debate falls short very quickly...
I don't think an object has intrinsically any need of saying anything... But I am pretty sure you didn't mean this...

But this question is not really clear about what you mean...

Do you mean:
Has the Photographer through his pictures a moral obligation to say something?
or
Whatever the picture or photographer is saying does it have to be intentional?
or
Does any photographs say something regardless its intention?

As you can imagine we can spend hours trying to clarify this question.

I personally believe that a picture/photographer does not need to say anything, neither objectively or subjectively, that happens as a natural process in the art making...
I believe in freedom and everybody should do whatever they please with their own art.

However, the photographers/artists I admire the most are the ones who have or had an agenda and successfully show it in their work by the technical means they deem necessary. In that respect I believe that the more you try to show conciously and intentionally your idea, or the more clearly an artist have something to say and know how, the more I like that artist.

On a second line, if I like what he/she says and agree what what he/she depicts that becomes my favorites artists, as in art it is impossibl;e to set aside subjectivity that comes in different shapes, as many as human beings are in the world...

Do we need to open a new debate?