You could say the same thing about "traditional" startups though - investors often invest just based on the combination of the idea, founders/team and maybe an early prototype. If the startup fails - nothing "bad" will happen to you either. Shares in a startup thats not publicly tradable don't really offer you that much security.
Unless you've committed fraud - but - I've been following the ICO market closely for the past 6 months and I can't remember any of the larger ICOs that were outright scams. Many people and smaller projects/websites will of course try to scam you online - but you should always do your own research and due diligence still applies.
I'm not sure I'd agree that "very few ICOs do right by their investors". It depends what you mean - there have been many successful projects out there that made people money. But if you mean "flipping" i.e. buying into a ICO just to try and sell it quickly for profit - that seems more difficult these days. But it might also be due to the current BTC rally.
ICOs are of course still in wild west territory as far as regulations go - there is a reason why Tezos calls it a donation. They don't want the regulatory hurdle. In fact almost all ICOs these days force you to accept that tokens are not shares in the company and don't "officially" entitle you to anything.