"Most people" is carrying
a lot of weight there and really just characterizes
some of the people who participate in a very specific culture that's quite new and anything but universal.
Most people around the world haven't really internalized the pointedly modern idea of "conciousness" in the first place and some people around the world and even in distintcly modern cultures don't find it a very fruitful way of making sense of their own experience, understanding it comceptually (as you might define a foreign word) but not engaging with it experientially (as you might in speaking a word). It's just a belief, a recently invented one, and one that only bears fruit alongside a constellation of other associated beliefs.
When it comes to actually navigating the world, most people don't orient themselves through such an abstract, intellectual lens let alone that specific one. They raise, eat, and sacrifice animals; they apply violence to other humans; etc etc -- or actively refrain from these things -- without thinking in terms of consciousness at all and often without thinking in terms of any comparably intellectualized rubric.
The way we treat animals and humans and fish and birds and forests and mountains and rivers is just an expression of culture. Cultures change over time and trade practices and beliefs with each other along the way, but there are nearly as many cultures as there are families in the world and to treat everyone like they do and should be part of your own, and that their failure to do so makes them morally detestable (rather than culturally alien), is extremely narrow minded and exclusionary.
In a pluralist, diverse society, like many of us live in, that kind of thinking often engenders strife, division, and eventually violence -- which I'm going to guess is something you don't want to add to the world.