I'd like to share my own personal anecdote from going to a Catholic school in Saskatchewan for 3 years, despite not being a Catholic.

• We were taught basic sex ed in grade 2
• "Religion" classes were taught from a historical perspective. For example, when talking about Moses, instead of reading the Bible we learned about slavery in ancient Egypt. I don't think I ever picked up a Bible in the few years I went to that school.
• We were taught evolution and the proper geological history of the Earth. What I mean by this is we learned that single-celled life began in the Archean era 4500 million years ago, all the way up to the Cambrian explosion and whatnot. There was never a single mention of Earth being 6000 years old or any of that. I didn't even know that was a belief people held until much later in my life.
• Kids had control of their education from Grade 1. If you didn't like your teacher, you were free to change classes at your own discretion. If you didn't like what you were learning, you were free to take on a more advanced form of a different subject on your own time (within reason, of course). I was able to do more advanced mathematics on my own time, at my own discretion, instead of art as long as I did some minimum of work in art.

I moved to Vancouver after a few years in Saskatchewan, and I went to what was considered one of the best elementary schools. The difference in quality of education was pretty startling. We covered far less advanced topics, had no freedom to do additional topics without significant paperwork and meeting between parents and teachers and staff, and the classrooms were in general much more overcrowded and underfunded.

In short, the education I received in a Catholic school in Saskatchewan was far more liberal, progressive and of higher quality than what I received in a public school in Vancouver.