This has been said before, but secular is not the same as atheist.
I'm an atheist, but I'm all for people being able to believe and worship as they fit.
As long as they/their representative institutions don't believe that their beliefs also give them the right to tell me what I can and cannot do.
Secular----->totalitarianism
Nope. Not even close.
Secular states - those that espouse a non-overlap between the public (government) spheres and personal/religious spheres - generally have greater degrees of personal freedom than states that are less secular or overtly religious.
Officially atheist states, exemplified by Cuba and North Korea, aren't secular, as the religious sphere doesn't official exist, or is officially suppressed.
Generally, suppression of beliefs is also correlated with suppression of freedoms in other areas and authoritrian or totalitarian regimes.
Secularism is generally attributable with open regimes with classical Liberal governmental structures. If you look at countries that have the highest degrees of personal freedom, they also tend to be among the least religious or most secular states. This is particularly true for Western, Liberal democratic nations.
Nations that top freedom indexes - such as New Zealand, Hong Kong, the Netherlands, Australia - are closely correlated with a low importance of religion in the country.
Many of the most religiously repressive countries - Saudi Arabia, Pakistan, Burma, Somalia, Sudan - are also among those where religion is the most important.
Religion is also important for authoritarian/totalitarian regimes, if only as a competing power structure, or a convenient scapegoat for their own failures.
Saudi Arabia, Iran and Sudan
Saudi Arabia, Iran and Sudan
Communism is the result of secularist eliminating the guidance of religious ideals resulting in a totally secular ideology.
Communism is an economic and social movement, first and foremost. Marx and Engles could have eliminated the enforced atheism from the communist ideology with very few implications for the rest of the system.
Unfortunately, their particular formulation of communism was essentially a conversationalist ideology that couldn't suffer competing power structures within the society, so elimination of the power of religious institutions was deemed necessary for the survival of the 'revolution'. If communist philosophers and ideologues had been more accommodationist and less confrontational, its interesting to speculate how different Russian and indeed global history could have been.
Communism is the result of eliminating capitalism in the economy and class distinctions in society, resulting in a command economy that centralises power in the hands of an a few, leaving the entire edifice open to strong-arming and authoritarian exploitation.