Quick answer: It is based on saying it is but indirectly it is not neutral.

A study of the question

Secularism is acting neutral in towards religion. It inevitably assumes that religion is man-made and thus that non-religious and religious must be treated equally before the law.

The reality is that there will be exceptions to this rule like there are in every other.

And to say that you are neutral towards religion means that you regard all of them as man-made. The person who believes her faith is factually correct in what it claims

Secularism is the view that the state must make its own decisions and treat all information about how to do this for the best as coming from man and not God.

Secularism is not neutral towards religion. To ignore the supernatural doctrines and morals of religion is neither encouraging them or discouraging them. And it is both.

Secularism is not a passive tolerance of religions. Rather, religion is treated as irrelevant and in this way all religions end up being treated as equals. Religious tolerance is always arrogant for it is about a person of one faith putting up with somebody of a different faith. The other person is not considered an equal.

Secularism is not an optional right or a privilege - it is a basic and fundamental human right.

It is not a necessary evil but something to be celebrated.

Secularism is not a belief system but a method.

Secularism is about being fair to people of religion and people of none by treating them all the same. The state does not meddle with religious institutions unless they do grave harm. And religious faith is to be kept out of state affairs.

Secularism treats non-religious groups, religions and religious groups equally.

Religious tampering with the state however is a worse evil than the state tampering with them.

Secularism ignores God’s rules and service to God to put people first and animals second. It is not true that secularism is neutral concerning God. Not deciding is making a decision. If you say one must have no dogma or opinion, then that is a dogma or opinion itself.

Secularism does not oppose religion except in opposing any religious entity that claims to know the truth. Secularism affirms that it does not really know and acts as if no religion really can know the truth better than anything else can.

If a religion differs from others considerably and is the truth, then its rights come first. Thus secularism opposes religion in the sense that it is neutral in religious questions and religion forbids such neutrality. Secularism is opposition to the belief that divine rights matter more than those of people. It cares about what we need not about God. It is based on the notion that no religion can be known to be true so you treat them all the same - the religion cursing Jesus is equal to the religion that blesses him.

Secularism is intrinsically atheistic. It cannot allow a religious person to argue that they must discriminate against another for their conscience says they must. That would drag secularism into the area of judging if a religious person is sincere and to judge that you have to judge if a sane person would believe what the person claims to believe. That means examining if the belief could be true and if there is good evidence in its favour. It would destroy religious freedom and cripple the nation in court-cases. It is clearly unfair for one person to suffer just because another claims to believe something.

Secularism is about structuring the state in a religiously neutral that is non-religious way. It is not the absence of religion but giving religion its proper place.

It is anti religion when a religion teaches it should have a say in the running of the country or when the religion undermines human rights.

Secularism is not about nations that have different religions in them and motivated by how you cannot please them all so keep them all out of state affairs. It is about a principle – secularism is a fundamental human right. Secularism should not try to secularise the people but should hope that they will do that themselves for that safeguards a fundamental human right.

People who won't admit that religion is a social construct like a club and who won't admit that you cannot use your current religious view which may be totally dismantled by next week or which you may only imagine you hold, refuse to confess that religious rights are less important than human rights, such as gender rights, sexual rights etc.  The state if it won't obligate a religion to do inter race marriage or same sex marriage may say, "We respect religious freedom."  But that effectively denies that all are equal under the law.  You may say the couple should find somebody to marry them but not anybody from the religion.  But then you are failing to see that though it is true the religion is discriminating, the entity doing the legal discriminating is the state.  It is not the religion that makes the exception to equality law but the state.  The exception smashes the rule.  Equality with exceptions is inequality.  Religion is disingenuous if it argues you are against its religious freedom even when you take care to make sure your target is the state with the effect on religion being a knock on effect and not a direct one.  The state is forced to tacitly treat religion as a sort of magical or divine institution.  Its man-made period.