The separation of church and state is a constitutional right. Standing up for it does not make one anti-religion. Because I don't want a creche on the front lawn of town hall doesn't mean that I don't celebrate Christmas - the true meaning of it. It means that I understand that we shouldn't have religious symbols on government property. That doesn't make me anti-religion. It means that I celebrate that this country was founded on religious freedom.
A constitutional right? Don't think so. That phrase was used in letters by Jefferson and Madison but you won't find it anywhere in the Constitution or Bill of Rights.
What you have is the first part of the First Amendment of the Constitution - "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof..." And obviously the debate comes in how that's interpreted and applied.
I wouldn't call somebody, like yourself, "anti-religion" simply because they don't think religious symbols should be on government property. Although, that does bring up questions about "In God We Trust" on our money, religious symbols in the national capital, etc.
But I would say that there are some on the secular left who misinterpret and misapply the "separation of church and state" phrase to isolate and minimize religion as much as possible.
