Atheists don’t have a definition of truth

Belief in God is not necessary to understand what truth is. I think many religious folks wrongly think that it is because of how they decide what is true or not: by total reliance on a chosen authority. 

There are several types of truth in philosophy. The one to which I hold is the “correspondence” theory which says:

“To be true is to accurately describe – in other words, match, picture, depict, express, conform to, agree with or correspond to – the real world or parts of it. For example, the proposition that a cat is on a mat is true if a real cat is on a real mat. Otherwise, that proposition fails to be true.”

https://www.rep.routledge.com/articles/thematic/truth-correspondence-theory-of/v-2#

This makes far more sense to me than slavish devotion to my interpretation of the writings of bronze-age goat herders who knew less about the world they lived in than an average fifth grade student today. 

Scientists are atheists’ “gods”

This misconception arises because the religious don’t understand that they have a different way of determining what is true than atheists.  By and large, religious people determine what they think is true by authority. They pick an authority to follow and that authority tells then whether something is true or not. In the case of most fundamentalist Christians, that authority is the Bible, hence the bumper-sticker maxim “The Bible says it. I believe it. That settles it.”

This would be disturbing enough, but faithers not only pick a source to blindly follow as a source of truth, but they wrongly assume that the rest of us must do the same thing, but with a different authority. They think we pick a few scientists and make THEM the infallible source of truth, but that’s not the case. Many atheists understand the scientific method of formulating a hypothesis, testing that hypothesis with evidence, and publishing your findings for peer review and replication. It is that PROCESS upon which many atheists rely for finding truth, not any scientist in particular. 

Atheism says that the cosmos and everything in it arose by random chance. That's ridiculous!

Atheism does not say any such thing. Atheism is nothing more and nothing less than not saying "there is a God." It does not present views on cosmology, biogenesis, or anything else.

Attackers of atheism will often construct straw man arguments that begin with the words "Atheism says" or "Atheists say". Because atheism literally says nothing, these arguments can be dismissed out of hand.

I don't have enough faith to be an atheist

You do not understand what an atheist is. Most atheists are de facto atheists. That is, we do not say with surety that there is no God. We simply do not see evidence to assert the existence of such a God, and so we don't. Faith is required to make an assertion without evidence. Since the atheist does not make an assertion, no faith is required.

Atheism is a religion

First of all, I find it interesting that you would want to call atheism a religion at all. It is almost as if you think you can do some damage by saying it is “just as bad” as your worldview.

Atheists say that there is no evidence for God therefore they are certain that he does not exist, but that's a fallacious argument.

Indeed it is, but most atheists do not take the strong position "I am certain there is no God." Most atheists simply do not make the assertion "There is a God." There is a difference. most of us are "de facto" atheists as described on Richard Dawkins' excellent "Spectrum of Theistic Probability". 

No atheist can prove that God does not exist!

It is absolutely true that I cannot now, nor will I ever be able to disprove the existence of God.  However, here is a partial list of other things whose existence neither I nor anyone else can disprove: