LOL... The law is not wholly subjective, but anyone who says that it is objective has, I believe, very little experience with it.
It in no way specifies or mandates secular education.
Sure does. First Amendment establishment clause. If you take my money at gunpoint to force your religious doctrine on my kids against all of our will, that's an establishment of religion if anything is.
It specifically prohibits the government from establishing and favoring non-theistic pursuits.
I trust this is a typo. If you really mean what this literally says, you are crazy, 'cause you're literally saying you think the Constitution only permits the government to establish or favor theistic pursuits. Where are we, Saudi Arabia? Iran? This is the first time I've heard we live in a Theocratic Republic...
I mean, sure, the First Amendment outlaws establishing atheism as well as theism, but not secularism. It permits (mandates, really) secularism. (Of course, you do have a tendency to get "atheism" and "secularism" confused...)