How can you say there is a God, when stuff like this happens?

Easy -- just take out the useless comma.

Humans are to blame for much of the suffering. They fight wars, commit crimes, pollute the environment, often carry on business in a manner motivated by greed rather than concern for their fellowman, and sometimes indulge in habits that they know can be harmful to their health. When they do these things, they hurt others and themselves. Should it be expected that humans would be immune to the consequences of what they do? (Gal. 6:7; Prov. 1:30-33) Is it reasonable to blame God for these things that humans themselves do?

Satan and his demons also share responsibility. The Bible discloses that much suffering is because of the influence of wicked spirits. The suffering for which so many people blame God does not come from him at all.—Rev. 12:12; Acts 10:38

If you reject the truth of God, with Him being the one and only source of all that is good, you cannot say that what happened in that video is bad, since in a rejection of God, you have no standard of goodness.

I didn't watch all of that out of respect for the dead and their families, but I will say this.  Sin is really about victims of others' sin, not about people being punished for their own sin, and in a world where there are internal combustion engines and the like, people suffer horribly for the sin of them being permitted.  This isn't about God but about human wrongdoing.

CUZ IVE KNOWN HIM PERSONALLY SINCE 1976!

IM not doing links..GOD IS NOT AFRAID TO TAKE RISKS and He gave us free will!

The other day I passed a BMW on the side of the road.  It has leaking oil out the bottom.  Steam was coming out of the radiator.  Its bumper was about 50 feet away from the rest of the car.  And a large portion of its front passenger quarter panel was pushed into the engine.  I never said to myself that there apparently is not a designer for that car or it would not be in that condition.  I realized that its condition was probably due to the pick up trunk a few yard away that had hit it.

To look at the condition of the world, which has been hit by a pick up truck called sin, and to say that is prefect that God does not exist is just as much nonsense.  

Jesus was asked this same type of a question.  He was told about 6 men that were building a tower and it fell over on them and killed them.  They asked Jesus if this was because this men were worse sinners than everyone else.  Jesus started by upping the ante further.  He reminded them of several people who would be slaughtered by the Romans only a few days before in the middle of making their sacrifices to God.  Surely if there was a god, he would have protected people who were in the middle of making offerings to him.  

Then Jesus gave the answer.  He simple said, "Repent. because you will also likewise die."

Everyone dies.  And it is always a tragedy to those left behind.  Bad things happen to people.  And there is nothing that you can do about it.  The only thing you can do is be sure that you are right with God before it happens.

There are times when God does step in and do miracles when it serves his purpose and furthers his goals.  But most of the time "free will" is in operation.  That means that God allows us to make our own moral decisions.  But then we also pay the consequences for those decisions.  If God were to step in everything someone does something wrong, we would all end up as mindless zombies, unable to make a decisions.  Sure, we would lose suffering.  But at the price of losing love, sharing, goodness, character, and everything else that makes life worth living.  We would lose the good along with the bad.  That every thing that makes us "human" would be lose - our free will that allows us to grow, love and improve.

Evil is not proof that God does not exist.  It is only prove that man is need of help from him.