I know it is just me, but while I am comfortable doing many things alone, going to Disneyland or on any cruise is not really one of them. Especially a Disney cruise. Maybe it is different for a woman because strangers will be more likely to talk to you, but a man sailing solo on a Disney cruise just because "he likes cruising" would looked upon pretty suspiciously, in my opinion.
I know I once took a solo cruise on a major "premium" cruise line (not Carnival, NCL or Royal Caribbean) and hence not a lot of singles were on board, and I did not enjoy it much at all. No one really wanted to talk to me. The few singles there were were not my age.
To me cruising is better when you have someone to share it with. Get a roommate and share a cabin & save money. Or if you are going to pay the singles supplement anyway - then take a friend! A free cruise, who wouldn't want one?