Incredible.

Rating: 9/10 (19 March 2020)

First of all, the movie was spectacular, the setting is presented wonderfully and the entire movies exposition is done through visual storytelling, and typical methods of exposition such as newspaper articles are actually relevant here because there is no way to unveil information through sound.
The silent scenes make moments more impactful than booming music would. Although it is used to build suspense during thriller scenes, It is often juxtaposed with deaf silence to give us an insight into the perspective of the daughter.
I want to address every problem I see people listing in this movie and why their points are illogical themselves, despite them trying to point out the illogicality of this movie.
"Why didn't they just live at the waterfall"
They can't just build a house... They were using real pre-existing structures/ shelter because that was the only realistic option, how would you collect resources to build a shelter if you can't make a sound?
"It doesn't tell us how many there are"
We can only go off the knowledge the family have. The dad has a note stating that 'Only 3 are known so far' and that's all the audience has to go off as well. It's their lack of knowledge that makes the thrill all that more exciting.
"Why did they have a baby"
Well are you really going to avoid sex for the rest of your life?
And its also tied into a character arc. The mother lost her youngest, she wants to fill the void with another child. Simple.
"Why don't they set up distraction sounds"
The monsters would run to it and destroy it instantly.
The reason they get used to the waterfall is because they literally cannot destroy it. But they could destroy speakers or anything else planted by a person.
"If guns could kill them the whole time then-"
No, the gun could only effect it once it was weakened by the sound amplification.
"Why did they survive but not the army"
Probably because the army tried to directly attack while civilians planned and evacuated covertly.
"Why didn't she remove the nail"
Didn't exactly have time to did she...
I really think people are going too deeply into this. For the idea itself I believe they did close to the best they could with it. Obviously I have points too such as how did the monster get in the mattress covered bunker and how did the mother escape the room (they completely skip over it). But overall I think it was amazingly shot, acted, scripted, and it paced itself incredibly well to build good suspense and not rely on jump scares.
You say the creators didn't think deeply enough, but from the looks of it, the majority of nitpicky negative reviews are thinking on more of a surface level then the writers.