He brought attention to his tax evasion for other reasons... but is it difficult to acknowledge that the direct legal cause of his jail time was evasion?
The claim being made is that the authorities wanted him in jail one way or another, because he was a gangster. Tax evasion just happened to be the charge they could make stick.
The counter-argument is that some authorities have always wanted to jail some people, but haven't been able to. Capone was jailed because he was caught on tax evasion; the mechanisms to why they looked at his tax records become lost in the argument around causality, which I don't think is fruitful in this context.
