They're not.

Some don't like Ripple from a purist's, decentralised crypto-anarchist perspective, which is fair enough I suppose, but it's no use countering them with compelling arguments for XRP - they won't change their minds. Logic isn't effective against an ethical position.

Others didn't get in early and regret it. Not much can be done about that now. Except if you really believe in XRP and see the potential, then getting in now is by no means too late.