From my soap box, the religious self-policing, to me, is one of the more disconcerting aspects of the education system in the United States. As a personal observation, if a parent is worried that a single teacher providing an intentionally unbiased perspective on a philosophical topic is going to challenge a child's beliefs to the point where it overcomes a family's and church's indoctrination then it isn't the new perspective that's the problem. To this day I believe that "core curriculum" should include logic and philosophy with an emphasis greater than all other topics.
For example: This question
> Why is 1+0 = 1 and not 10
Attempt to find an answer will generate more questions and it is a journey down the rabbit hole. Sometimes you don't want to do that.
And upto high-school I learnt things that were based on assumptions that I kept questioning. Internet brought be some peace in my college years. Unfortunately, nowadays internet is also filled with fake/wrong/hoax/biased stuff.
First, hold one apple in each hand. Ask your child how many apples you have in one hand, them the other hand, then the total.
Then, hold two apples in one hand, with the other hand empty. Point out that you have two in one hand, and none, therefore zero, in the other. Have your child count the total number of apples, 2, and explain further how zero stands for no quantity. How when you have zero of something, you really have none.
First, we simply don't have evidence for such life, so we can't say that it does exist. We also can't say that it doesn't, and certainly not that it couldn't, but those are topics that make for good science fiction rather than incredibly fruitful topics for scientific inquiry. With that said there's certainly some really interesting stuff going on all the same! https://en.wikipedia.org/wiki/Xenobiology
That leads to the second thing that's stopping it from being a heavily studied topic, which is that it's currently getting crowded out by the search for conventional life that happens to not be on Earth. The argument here goes 'yes, life elsewhere might not look like life here, but we know a heck of a lot more about life here than we do about how other, highly different life forms could work, so it makes more sense to focus our study on life that looks like the greater 'us' of earth-bound life.'
I've really enjoyed the discussions I've had on this topic, so I hope this was interesting to you. Sorry your teacher acted like a jerk!