Why can't aliens be alien?

I love all sorts of aliens, but in this specific movie, I liked that the aliens were very similar to humans: the whole reason for their coming to Earth was because humans had discovered an earthlike planet and sent a signal there. It stands to reason that an earthlike planet would produce lifeforms similar to ours. I loved the double set of opposable thumbs too.

I don't think it's a Hollywood thing, but rather a movie thing in general. Can you think of non-Hollywood aliens that are less anthropomorphic?

"Occasionally I'm callous and strange."

E.T., War of the Worlds, Independence Day, Predator, Alien, District 9 all had interesting, entertaining alien biologies. They don't have to be "realistic" until we actually discover them in real life!

you have to remember that all Hollywood science fiction alien invasion movies stem back to a time when the U.S. was inhabited 99.9% by christian people, who universally believed that humans were the pinnacle of god's creations, and that god was human like himself, so therefore all advanced civilizations would be human like as well (we considered ourselves to be civilized back then; our most advanced minds today realize that we are still for the most part barbarians).
Real aliens would probably be very unlike us; so much so, that they would be so much further on the evolutionary scale from us, that we would appear to them, as simple as ants do to us.

If you watch some of the directors interviews, Peter Berg clearly references some of the other kinds of aliens that he could have created or directed the creation of.

But he wanted more anthropomorphic aliens. I think this is probably better for audiences. The farther into "alien" territory you get, the less recognizable and understandable it becomes for the general audience member.

Sure, you could go completely haywire alien like Edge of Tomorrow and get really whacked out, but the audience will have a hard time connecting.

I'm pretty sure Peter Berg knew this.

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Ray, when someone asks you if you're a god, you say YES!

Do you remember Space Above And Beyond? Humans and Chigs do have common origins. So do the aliens and humans in Battleship.

One could argue that species that live in the same approximate environments, and share many of the same social and technological attributes would also evolve along the same lines, and share many of the same physical attributes.

That is to say, that if they are like us in so many other ways, then why wouldn't they be like us in still others.

Aliens in movies are for the most part simply designed to 1. be easily recognizable as the bad guys and 2. be just different enough from humans to ensure that their complete destruction bothers no-one's conscience and can be cheered on.
At the same time, they have to be similar enough to humans that not too big a stretch of the imagination is required to believe that their suffering is similar to our own. After all, who knows what a Ganymedian slime-mold or a many-tentacled one-eyed squid from Proxima Centauri is feeling? It may be completely indifferent to being shot, cut up, having its relatives wiped out, etc. - the satisfaction gained from visiting righteous violence on such creatures would be lacking.

When you think of it: humanoid form is pretty efficient. Really efficient. Run. Climb. Swim. Squat. Hunch over.

Would make sense, that humanoid forms would prosper on other planets with gravity.

But I agree: I would like to see some strange aliens too.