Because the little green men style of alien is constantly used to bash Christianity along with nationalist and the traditional values that we as Q-people are supposed to hold dear. Excuse us for trying to deny our enemies a weapon and cudgel to use against us. Little green men style aliens are a globalist fabrication designed to bring about the end times and how you're so blind to see such a bold face and hollow ploy despite looking through so much of the cabal's lies is really quite sad. You probably also believe the lie that men and women are equal, the races are equal, the nations are equal, and so many other false equality lies.
No, see, people who believe in the existence of totally mundane aliens are the ignorant ones. Ignorant of physics, chemistry, biology, and just basic engineering principles. Heat management ALONE precludes the existence of boring old little green men type of aliens of the kind you're thinking of, let alone anything more complicated.
Here's a bit of advice: if the words 'other dimensions' are ever used, it's basically an admission that they're not standard little green men style aliens since saying 'other dimensions' is just a materialist pseudosciencey fig-leaf for the genuinely supernatural, IE, angels, demons, and God.