First things first: it is not true that atheists don’t believe in anything that cannot be scientifically proven. They may also believe in things that can be philosophically proven, for instance. Morality is ultimately a philosophical issue. If there are good philosophical arguments for the existence of an objective morality, then, anyone who is willing to adopt the premises of those arguments can adopt the conclusion (i.e., that there is an objective morality).
Secondly: helping the sick, helping the poor, (not) stealing, and (not) murdering are actions, not moralities (objective or otherwise). People may choose to do them for any number of reasons—including, though not necessarily, because they are demanded by some sort of objective morality. Moreover, you are confusing yourself by saying that they are moral objectives, and therefore require morality to be objective. The word “objective” in the phrase “moral objective” means “goal.” That’s not what the word “objective” means in the phrase “objective morality.” One can have moral objectives (that is, goals) regardless of whether one takes morality to be objective or subjective.
Thinking racism is (morally) wrong is slightly different. If it’s supposed to be a true statement, then there would need to be moral facts to make it true. Many might be content to say only that racism is unjustified, irrational, socially counterproductive, and factually mistaken, however, which would not require a special class of moral facts. If practical and rational grounds are sufficient for condemning racist actions, then the lack of a special set of moral reasons need not bother us. Yet we may not even need to go that far if there are philosophical reasons for accepting an objective morality.
And finally: you seem to be conflating atheism with metaphysical naturalism. They are not the same. One can be an atheist and still believe in supernatural things. Jainism, for instance, is a religion that posits the existence of souls and an afterlife but rejects the existence of God. You are taking a small subset of atheists and acting as if they are representative of all atheists, which is not the case.
It may also be worth noting that some people think science does hold the answers to morality, and that the system which emerges from scientific research is an objective one. I happen to think that this is mistaken, but we should not pretend that the view does not exist or have any evidence in its favor.