Bear in mind this article focuses on religious education in primary school, which is straight up indoctrination from start to finish of each schoolday.

I'm talking prayers each morning, before lunch, before going home, multiple religious songs being sung every day, a heavy focus on stuff out of the bible depending on the time of year. Visits from priests, school masses, having to do the rosary during May. On top of this, schools do all of the preparation for sacraments during school time, which is what Atheist Ireland has been mostly referring to when they talk about exemption from religion classes. It can be very difficult to draw the boundary because as I've said above, the indoctrination is pervasive. We were never taught about other religions, only small aspects of judaism came up because jesus was from a jewish background.

So much time is wasted on catholic indoctrination throughout those 8 years of early education that could be better spent on things like languages and science. Speaking as somebody who has grown up in this education system and is now an atheist like a lot of my peers, it disgusts me to think about all the time that was wasted being forced to believe in a thing that imo doesn't exist because I didn't know any better. Add in all of the scandals that have came out recently which makes the feeling worse.

There’s probably many different examples and types of these things that vary from region to region around the world.

Here’s a US perspective.

I live in NY and there is a large number of Roman Catholics. Public schools here are not allowed to teach religion. Global and Social Studies classes are allowed to teach about religion but in an informational manner just about what the beliefs of each type are. I remember in like 7th and 8th grade learning about Islam, Hinduism, Buddhists, etc.

Direct teachings from scripture or holy text would have to take place in a house of worship. Church, Mosque, etc. This is because public school systems are state funded and there’s an established separation of church and state.

Back to my experience, about 25% of my classmates growing up were from Catholic families. To accommodate their need for religious learning, every Wednesday, after lunch, all the Catholic children were dismissed and bussed to their church where they had CCD (Confraternity of Christian Doctrine) classes for the remainder of that afternoon.

If accommodations like this aren’t met for a group of people that are a sizable percentage of the community it could be viewed as religious discrimination.

On the other hand, if religious teachings start to make their way into public schools, many interpret that as a direct violation of the US Constitution and an attack on religious freedoms.

This is an ongoing, ever present issue in the US. Especially in heavily Christian communities.