and your definition contradicts that which you provide for charity law.
No it doesn't. The are worded differently but the overall meaning is very similar between:
'The word “religion” is commonly, but not always, associated with belief in a transcendent deity or deities, i.e. a superhuman power or powers with an interest in human destiny.'
And
'belief in a god (or gods) or goddess (or goddesses), or supreme being, or divine or transcendental being or entity or spiritual principle (‘supreme being or entity’) which is the object or focus of the religion
a relationship between the believer and the supreme being or entity by showing worship of, reverence for or veneration of the supreme being or entity
a degree of cogency, cohesion, seriousness and importance
an identifiable positive, beneficial, moral or ethical framework'
What is clear from both is that neither humanism nor atheism are religions.