Because certain religions see Fengshui as paganism or witchcraft. It is a forbidden art for their religion and those who prefer "salvation" over the luck that Feng Shui gives will seriously take action against it. While others are just aggressively imposing their belief that Feng Shui does not make sense because there is no scientific proof about it.
Many people are very skeptical about accepting something different because they live in a bubble....
They don't know the diversity that exists in this world. For example: what in one country is sacred in another is food... this is crazy, but it's the world we live in, something absurd for someone can be normal for others.
People need to know how to live with this, adapting to the laws of each country, obviously, but looking for a certain tolerance for it.
i believe, when it comes to belief and culture of every person, is just respect them for what they believe in. if you happen to travel around the world, you will learn to respect the culture of the people, and be more open about diversities that you will encounter with them. it may or may not be against your beliefs, but the most important thing is to respect them.