Why do some people find it unacceptable to use the term "animals" in a context where the word excludes humans?

Humans are animals but many people don't like that connotation because of religion and what not. We work, live, take care of our families, reproduce, etc. just like other animals do. While we build buildings, cars, go into space, etc., we are animals none the less. Most animals survive based on instinct, but higher forms of animals, like humans, dolphins, elephants, etc, can form more complex thoughts and by having more complex thoughts, we can put them into action and build stuff.