You hear it a lot: teaching your kids to be an Atheist is no different and no better than teaching your kid to be a Christian/Muslim/Hindu etc. It’s brainwashing them, just the same.
I actually used to think this was a frustrating and somewhat valid argument. That is, until I actually became a parent.
Kids don’t invent God. They don’t usually require that you introduce am omniscient, omnipotent being into their lives in order to help them make sense of the world. They have what they need. Raising an Atheist (at least during the early stages) doesn’t require you to do anything at all. You just don’t talk about God. You don’t teach them about it. When they have questions, you answer them honestly.
That is very different from raising a religious child. In doing that you are forced to introduce a whole other realm of “reality” that they cannot see or touch. You answer fairly simple questions with complicated answers involving a man who lived and then died and was raised from the dead over 2000 years ago (Or insert other weird religious story here). You must teach prayer and how to behave in church. You must drill them on how to pray and how to incorporate religiosity into every day occurrences. You must teach them to rely on more than their own sensibilities. You must enforce the idea that they are being watched (and how every subtly you introduce it, judged.) You must introduce the idea of heaven (and by extension, hell) and salvation and the idea that everyone in the world is not equal. Some people are like us, and others are not. You teach them, before they have had the chance to evaluate the evidence for themselves, what is true and not true and demand that their tiny, developing brains embrace a world view that they don’t have a chance to test.
A child without religion experiences love it its truest form – unconditional and with no strings attached. Religious children learn very early on that love is often tied to the choices they make. That there is judgment to receive, guilt to feel and apologies to be made.