[Ichneumon]

But, of course, darwinism/secularism/materialism/socialism is not a religion,

Correct.

it is a philosophical worldview consistent with the scientific method; hence not covered by the First Amendment's Establishment clause.

Also correct.

That only applies to grubby fundamentalist Christians.

Incorrect -- it applies to the other kinds too, as well as to other religions.

[A.J.Armitage]

So, would you like to "establish" your philosophical worldview, and if so, how?