I often see people that are atheist, because of what the science tells. But I usually also see the same people don't really understand the science they use to justify their view. So don't this make this kind of people just as religious as anyone else, since their view is not based on knowledge, but belief?
I don't think many people are 'atheist because of what the science tells', since science doesn't speak to the presence or absence of gods. However, for example, a person who has been a strong believer in creationism and a young earth but is subsequently convinced by scientific evidence that the earth is old and evolution evidence is solid may wholly reject the religion that told him to believe the former, reasoning that if they were wrong about that, they were likely wrong about god, too.
I understand your point - there are people who are obviously not informed enough about the science they point to as reason for their disbelief for that to be a realistic reason for their rejection of faith. Sometimes I notice such persons are very young, in their teens, and I doubt if their position re god-belief is settled. They may change their minds on the subject several times as they mature.
Sometimes, though, such people, while they may misapprehend scientific concepts or appear less than well-informed, are making a valid statement because what they trust is not science, but other people who they respect and trust not to lie to them, and they usually have very good reasons for that trust.
I don't have any chemistry background, so science that entails a knowledge of chemistry is difficult for me to follow. However, I trust that chemists as a group, who have presented us with a whole lot of chemistry that works as advertised, aren't making stuff up. (Why would they?) So I don't 'have faith' in chemists/chemistry, I just see the results of their work and expect when they talk about chemistry, they are being truthful. So even though I don't understand chemistry very well, my belief that chemists are truthful is evidence based, not faith based. And that probably is the case with some atheists who reason that a scientific consensus on evolution and age of earth, whether they personally understand geology or evolution themselves, is good enough to accept as evidence based truth.