You are confusing diffusion with dissociation. Diffusion is a mixing of molecular gases, and dissociation is the breakdown of gaseous molecules into those chemicals within the gas.
Chemists tell us it is chlorine that breaks up ozone, and atmospheric scientists are saying that chlorine is coming from CFCs. Meanwhile, volcanoes spit out far more dirty, but chemical active, chlorine into upper atmospheric regions than dissociation could ever provide.
Required from scientists is proof that heavy and inert CFC molecules can and do dissociate into chlorine atoms which can move to the upper atmosphere to the degree required to outpace volcanic chlorine production.
Until then, I hold that modern environmental science is built on fraud.