On religion as a human activity and secularism

It is hard the argue against the fact that what is generally called religion is a human activity. What should be classified as religious activity can of course be dabated and which features of our society that should be attributed to religion is also so.
More fundamental activities, concepts and ideas can further be categorized to the activity of religion or not.
My proposition is then that the categorization of activities as religion is destructive. Religion is a very charged word. Further there are ideas claiming that religion and religious activity should be free from critique and the executor can often claim religion and be free of any responsibility for his/her actions.
It is slightly easier with culture and it us thus better to assiciate elements to a certain culture.