Political commentary has historically been a very important function of art. I can understand the concern regarding the use of DALL-E 2 for impersonation, but that can be avoided by simply making sure that the image contains adequate clues that it is not an actual photograph. A politician represented in the style of an editorial cartoon, for example, would clearly be representing the user’s view of that politician, and not the politician himself of herself.
DALL-E is a tool, and as such cannot be blamed, or praised, for the political views expressed through it. Therefore, its content policy should not exclude images of political figures, so long as those images cannot be mistaken for photographic images of the person herself or himself.