If there really are aliens visiting Earth, why would the government need to hide the aliens?

If there were aliens visiting earth, there wouldn't be just one country who knew about it. Many countries would know.

The Government isn't hiding them. Their UFO is parked openly on the White House lawn for all the world to see. Trump is busily collecting demon semen and alien dna to make a cure for Corona Virus. Keep up.

Perhaps because the chaos caused by the fictional radio drama "War of the Worlds" convinced them the populace simply couldn't handle the idea of space aliens existing.

Perhaps the aliens and the government had an agreement that they would not reveal their existence to the public until Humanity had advanced to a certain point (eg. Achieved faster than light travel) 

The government is controlled by aliens.

So cheeks remain unclapped

probably for their protection

Friend there really are aliens upon this Earth right now you don't want to really know who they are but I'm going to tell you. The Bible tells you who these aliens are they're wicked beings that were cast out of God's heaven. They're called demons. And they're hell-bent on the destruction of anybody that they don't like. That's pretty much the human race in general. They have made contact with the government's the government's know that these demons exist and are talking to them on a regular basis. The deal is very simple if you do what we want you to do will teach you how to build weapons and how to build technology and make you number one in the political game. If you don't will make sure that super germs and super viruses hover around your country until you're a third-rate country that's disease-ridden and full of famine and war!

You would think that if aliens are intelligent enough to to travel all that way from other planets, they would decide for themselves whether they want to be hidden or not. You would think they want to visit a few tourist spots and make videos to take back. 

It would take a spaceship from Earth something like 30,000 years to reach other planets that might contain life, so they must have found ways to travel faster than light or be extremely old when they get here. 

Any way you look at it, alien visits are not very logical.