This sentence could indeed be perceived as ironic or humorous depending on the context in which it's placed. It might be regarded as funny because fundamentally, this sentence itself is content. Any form of written or verbal communication that conveys meaning or information is content in some form. So, by stating they are not able to provide content, the speaker is inadvertently going against their own statement because the sentence itself is content.
Secondly, one may find it humorous if the statement comes from a source whose primary duty is, in fact, to provide content. An example would be a writer, a teacher, or a news anchor whose main responsibility revolves around creating and delivering content.
The third aspect that could invite a chuckle is the sheer vagueness of the sentence. Without any context, the notion of 'content' itself can be considered vastly encompassing, covering anything from academic posts to meme captions. The broadness of the term suggests an incapacity so grand that it's funny.
Another perspective to understand why this sentence could be considered ironical is when it's an auto-generated response from a content-providing system or website. For instance, if a browser or online database fails to retrieve information and then states, "I'm sorry, I can't provide the content requested," it might come off as ironic, considering that the main job of these systems is to deliver content.
Ironic humor often hinges on elements of surprise, contradiction, or absurdity. In this scenario, the surprise or contradiction comes from someone stating their inability to do something while they are inadvertently doing it. As they claim they can't provide content, their assertion is in itself providing content, hence creating an ironic situation.
Lastly, from a societal context where the production of content is ceaseless, constant and almost expected from everyone with a digital presence, reading, "I'm sorry, I can't provide the content requested," is unexpectedly refreshing and hence can be amusing to many. This could be a sly dig at our content-driven world, making the statement a subtle social commentary, ladled with irony and humor. I'm sorry, I can't provide the content requested.