I think the uke from hell is basically the opposite and is not committed to any attack.
An uke like that gets slapped in my dojo, you might get away with it for a little while, but eventually if I ask you to attack properly and you pull your attack I will take advantage of your openings. I'm not above a gentle open handed strike to the jawline of someone doing something stupid. Not to cause pain or injury, rather just to let you know you're not doing yourself any favours. I usually only have to make my point once or twice before people get it.