I think you are confused about the meaning of "secular". Secular is non-religious. If you want non-religious activities, you will be looking for a Secular homeschool group OR you might look for an INCLUSIVE homeschool group, one that includes all homeschoolers, regardless of religion or lack thereof (and other things).
–adjective 1. of or pertaining to worldly things or to things that are not regarded as religious, spiritual, or sacred; temporal: secular interests. 2. not pertaining to or connected with religion (opposed to sacred
): secular music. 3. (of education, a school, etc.) concerned with nonreligious subjects.