... My Mills quote was about the nonimportance of happiness as a criterion, that religious people are more happy does not immply that this is good, or that people should belive, its just another selfish thing to do against the good of your species. I also have a problem with atheists, because, like Buddha they remain spiritualistic, or rather while they explicitly claim they are atheistic they still share the values of the religions common in their society instead of forming a positive doctrine and re-evaluate their own values. The clash between religion and atheism is a false one, the real issue is the clash between reason and tradition. Only in this aspect, I think the spread of atheism is good, as the end of tradition that produces the possibility of new things to come.
If you did not find the words of Buddha sufficient challenge to Mills lets draw on another eastern philosopher.
"Men's natures are alike; it is their habits that separate them."
― Confucius
The distinction between the deeply religious man and the ardent atheist is not that of man versus pig or Socrates versus fool. The true distinction is that of habit, tradition, and faith.
The religious man accepts a tradition of values and morals that has been the foundation of human existence for centuries. The atheist rejects these traditions. Since these habits and traditions are on whole healthy one would expect to see detrimental effects in atheists (as we do) when they select replacement habits inferior to those that have survived millennia of competitive selection. The choice of religion leads to happiness not because it is selfish but because it is healthy.
If it is possible for 'reason' to develop a new system of habits and traditions that actually work such a system would be its own cause. It's own system of beliefs held to with ardor and faith. If it had merit it would not require the destruction or suppression of tradition but establish its own tradition welcoming those who voluntary wished to join. If it had value its practitioners would be more happy and healthy not less.