First of all they are basically fully centralized, which stand against the true purpose of cryptocurrencies
I don't want to defend XRP here, but....
What's the true purpose of cryptocurrency? there's no such standard, as long as it's a digital/virtual currency that using cryptography to make it secure, it will be said as a cryptocurrency.
Any cryptocurrency don't need to be decentralized like Bitcoin, it's no need to have a high volatility like Bitcoin, it don't need to be transparent like Bitcoin. It don't need to be same like any existing currency, if it's same, what's the reason to create it?
I'm surprised that you don't put decentralization at the heart of cryptocurrency. Yes, cryptocurrency has crypto-based encryption at its core, but the original idea of cryptocurrency was that you don't need to trust your money to a third party. And the centralized system is in fact a third party. So you're wrong to say that cryptocurrency shouldn't have decentralization.