So you are fighting hard to indoctrinate children in schools?
I believe he's a humanist as am I. We fight to to prevent indoctrination in school, hence no class prayer or creationism in public schools. Perhaps you are unsure about the difference between indoctrination and education. The former involves only repetition, not evidence or sound argument, as with Sunday school creationism indoctrination. Contrast that with a university course in evolution, in which the evidence available to Darwin and his interpretation of its significance is presented. No part of that is likely to be repeated. If you miss that class, you'll need to get a buddy's notes or lust read the text if you want to answer test questions from that lecture correctly. Another important difference between the two is that your professor won't ask you if you believe it or chastise you if you don't.
What research do you have done to prove religions indoctrinate but not atheism?
Prove? Did you mean learn?
The same research usually done to acquire information: experience, trial-and-error, observation of how people think and behave. I've interacted with hundreds of theists and atheists. I've been both myself.
How does one indoctrinate atheism, and why would one?
My parents were atheists. I grew up until about age 19 without religion. They never mentioned the word atheism. They never discussed gods. I wouldn't even have known religion existed or heard about gods had it not come from the television or other sources other than my parents.