Or some of the photos he uploaded contained nudity. Or some parts of his profile or some of his photos were considered hate speech under the community guidelines. Or his profile was considered "self-promotional" (e.g. advertising his work or services) or contained addresses or other means of contacting him. We know nothing.
Usually banned users get feedback about being banned. The ones usually not getting feedback are spammers - they are being shadowbanned to avoid spammers being able to deduce their ban cause and circumvent the anti-spam measure.
