the definition that uses the word "purpose" is only one of many definitions. Atheism is a religion, but if somehow it is not, it is so extremely close that it may as well be considered religion.
Can I summarise your statement? "Atheism is a religion. Even if it isn't a religion, it's a religion".
This is not an argument, it's just a self contradictory statement.
You are almost there.
Any human that lives and thinks has his own personal religion... in addition to whatever formal religion he may have. Only if he is dead does he not have a religion.
You are finally getting it.
You admit that your arguments are self contradictory statements. You're right, we *are* getting somewhere.