Because religious conservatives love to cherry-pick what they like most about philosophies and ignore what they don't. Since she espoused Absolute Capitalism (i.e., corporations can do anything they want in the pursuit of profits completely free of government controls, even if it harms people and/or the environment), well, they loooove that part of course. They also love that Objectivism is against involuntary taxation, antitrust laws, minimum wage and child labor laws.

They conveniently forget that Objectivism is also very Pro-abortion. They completely understand that it is anti-censorship, but take that to the extreme by justifying all opinions, including hate speech.