The police are not always capable of helping you when you need them. The oft-quoted saying is "when seconds count the police are minutes away", and it is very, very true. Guns used in lawful self-defense, which often involves nothing more than drawing the gun causing the attacker to flee the scene, stop an incredible amount of crimes every day. More so, the reason that gun rights are so fundamental in the US is that they are intended as a key tool to prevent the establishment of tyranny. It's easy to write that off as some outlandish idea, or as some preposterous hypothetical but that ignores the lessons of history. In the 20th century, of the 10 most advanced and most powerful nations on Earth only 2 of them never fell under the boot heel of an oppressive totalitarian regime. Fortunately mass use of guns in the hands of the populace was not needed to forestall tyranny in those 2 remaining countries but these statistics are a powerful reminder that tyranny is a very real threat and it will probably forever remain a potential threat to freedom.

As far as acquiring a gun, it is not as simple as many fictional portrayals. Most of the time you will go to a gun shop and pick out a gun and then you'll have to fill out paperwork and the gun store will do a federal background check on you to make sure you are legally allowed to own a firearm. Depending on the type of gun you purchase and the state you live in there may be a waiting period before you can take ownership of your gun.

As far as the ridiculousness of the TSA's rules, those are non-sensical and should not be used to inform other law making.