If I could come up with something better, they would have done that. Absence of a better solution does not imply any fitness of the proposed solution. Until such time that someone comes up with a better idea, I am sticking to public blockchains.
Don't give up so easily! If you're going to make a stance borne out of principle, why not follow through to outperform the suboptimal solution that you dislike so much?
Innovate. Put some skin in the game. That's what I would do, anyway.
As it stands: If any of the folks involved in the trusted setup was honest, then it's secure. It takes a 100% corruption to make it insecure. I think that's acceptable until a better solution is proposed.
Except that they had to rush the launch because they're a for-profit, centralised company, with investors that are demanding return on their investment. Thus they went with a shoddy, half-baked attempt at a trusted setup, with a whole lot of hand-waving to make it seem like it was done securely.