I have money for whatever reason. I pump it through a business of mine, paying taxes, etc. Normally this is totally fine - I'm not using it to commit fraud against investors, I'm paying taxes, etc. The important thing is that no one is being harmed, it's just me seeking some privacy in my own finances, and perhaps losing some money for the privilege (I may be spending post-tax money).
Or perhaps it's simpler than that. I have a bunch of money in geographic location A, and I want to spend it in B, so I put it in a suitcase and walk/fly/drive on over.
Now LE comes along and says, gee whiz, our jobs are really hard having to catch criminals doing criminal stuff. You know, let's make it illegal to use your money as you like, to have any sort of privacy in your transactions. Tada, now they can just go after people for moving money around.
The sad thing is, they've won. They've made "money laundering" sound like something serious, instead of totally made up to make their jobs easy, and people seem to support such laws.
Maybe they'll call encryption "data laundering", "bit smuggling", "safety obstruction" or something catchy to get people against it.