There wouldn't be a second transaction (the front store) if it weren't for trying to pay taxes on the first. So that's not really a defensible line of reasoning. Only, perhaps, if the tax rates would differ.
Sure, so if you want to use circular logic to say the real crime of money laundering is tax evasion, when money laundering actually results in more taxes being paid, that's fine. But don't expect that to be a persuasive moral argument for making money laundering a crime.
I didn't say the real crime of money laundering is tax evasion. The real crime of money laundering is obstruction of justice. But taxes are certainly being evaded, too.