"Trading is among one of the few industries out there where you don't need to have anything like a customer."

Yes, but knowing how to trade is obviously very important, it's not just picking stocks, it's risk management, regulatory issues, and tons of industry specific knowledge.

That said - if they have 'tech that works' they should be able to partner with a few financial people and wrap a fund around it without too much trouble.

That so much negativity is on Glassdoor is really a bad sign.