A secular society is one which treats all religion equally. However there is a religion which believes in converting other religions to its faith. Therefore is it true that it is impossible to create a truly secular society ?
With religion, it is impossible. A secular society can be one where there is no religion (like a comment said).
Otherwise, any "religion equally" society would have to accept also that a group of members considers all religions fake and want to be free from religious rule, teachings and interaction (or, another case, as the author mentions - that want to assimilate the others into their own religion, which most of religions actually do), therefore, there can be no true equilibrium there.
Currently, modern 'democracies' are generally self-recognized as secular, but they are actually not. They accept some religions (only in theory equally) but directly reject and/or ban others as sects, evil, unconstitutional or even on criteria as 'not enough members'.
I would recast this as a: "truly liberal society." Religion is a very vague term, is Maoism a religion? Confucianism? Is anything that authoritatively prescribes actions on the basis of a teaching presumed to come from those most qualified to produce a sound teaching a religion? Ergo, also any so-called rational doctrine? Catholicism is the true meaning of "religion" in Western discourse. It was opposed chiefly to political morality or "political virtue" in Montesquieu's phrase, i.e., political virtue thought as in Cicero's On Duties. What it means in this context, the only tangible one, is Universal rather than locally interested prescriptions to right behavior. The world, not this people or this Fatherland.
Now, is Liberalism a religion, the claim everyone can do as they like, think as they like, so long as it does not injure others? Yes, in that it is a universal dogma, if you like. So, either one makes a strict or tyrannical Liberalism, all doctrines that don't agree with our founding principle are outlawed or to be witheringly curtailed, or one does not really live as a Liberal, but only sort of glances at the teaching. This is why liberals in the US are always going about slaughtering people, such as with the crime in Lybia, because there is no half-way house except the old style of political, i.e., locally interested virtue. That path is not open because one constantly hears of the most remote parts of the world, and, a fortiori, does business with every quarter of the globe. If it is thus granted that Liberalism is what's meant by the vague notion of "secularism", and that ideologies are universal and thereby like religion, i.e., like Catholicism, the issues comes clear.
It is possible- if a functioning democracy is secular in character. And the religious ethos is humane.
The separation of religion and state is the foundation of secularism.
It ensures religious groups don't interfere in affairs of state, and the state doesn't interfere in religious affairs. Secularism seeks to ensure and protect freedom of religious belief and practice for all citizens apart from freedoms of thought and conscience to apply equally to all – believers and non-believers alike.
In a secular democracy, all citizens are equal before the law and parliament.
Secularism champions universal human rights above religious demands. It upholds equality laws that protect women, LGBT people and minorities from religious discrimination. Equal access to public services Secularism is not atheism-
it is simply a framework for ensuring equality throughout society – in politics, education, the law and elsewhere – for believers and non-believers alike.
Religious people have the right to express their beliefs publicly but so do those who oppose or question those beliefs.
Secularism is the best chance we have to create a society in which people of all religions or none can live together fairly and peacefully.