Because in America, that statement is so heretical and antithetical to what the average American thinks America is, that most people probably wouldn't even be mad at you for saying it: They'd think you were legitimately unwell/insane.
It's on the same level as saying "I hate liberals and am not conservative".
If you don't want to antagonise people too much maybe you could go a less negative route? Instead of saying what you are against you could say what you're for. Instead of saying "fuck small businesses" say that you prefer democratically run worker's coops as they provide a better outcome for workers and the local community both economically but also on more immaterial levels by increasing freedom, self-determination and happiness for the majority.