So in short, is there no conclusive evidence linking it to autism?

Kennedy hears that there is no conclusive evidence linking tylenol to autism yet assumes the causal relationship exists. (It just hasn’t been proven yet.)

Any rational person hearing that there is no conclusive evidence linking tylenol to autism assumes the causal relationship does not exist. (But acknowledges that the causal relationship has not been disproven.)

A better summary would be “Kennedy acknowledges his claims about Tylenol are not supported by evidence.”