Am being a cleanfreak or are they dicks?

Neither, really. You just have a different standard of cleanliness than your roommates do, and since your roommates outnumber you you're kinda screwed.

Choose your battles. How much longer do you have to live with these people? Do you have other options? Can you tolerate living with their lack of cleanliness? You can't force them to be more clean for your sake if they don't want to be and while I would pick your side personally I know plenty of people who wouldn't. Everyone has their own level of tolerance for messiness and what they're comfortable in, and in a roommate situation with no close personal relationship between them there's not much reason to live up to any one person's wishes.

With that said, I see no reason why they would stop you from cleaning? That is, if you want to see something cleaned, and you're happy doing it yourself, then why on earth would they object? I'm not sure why you're even asking for permission. You live there, and it's almost objectively better to have something be clean than dirty.