If you're smart enough to tell a good investment from a scam, why don't you have enough money to be an accredited investor?

Or, in other words, by the time the plebes are jumping in on crazy new financial scheme X, you're well enough into bubble phase that restricting investment is probably fine.

Have you seen the requirements to get accredited? How do you get there starting with a modest capital without taking insane risks?

But beyond that I don’t understand why regulation on investment is seen as ok, but regulation in loans to prevent people to drown in debt (which is kind of worse) is frowned upon. I’m not even the most liberal person, but if people are free to lose more than they have (or buy guns, or destroy their health with sugar, or what else) then why are they not free to put their money where they want?

Because lots of people losing all of their money on bad investments has effects on the whole economy, see the Great Depression.

But when it’s institutions like in 2008 it’s ok?

No, that's a problem too? Why does everyone respond with "oh so you think payday loans and subprime mortgages are OK?"

Do you actually want to go back to a time before the SEC. That's how you get a Great Depression.

You're a smart guy, solve it.