Of course the market says both of these tokens are worth billions in market cap. It treats it exactly like a cryptocurrency, feeding on the cryptocurrency hype. Clearly the market doesn't value decentralization to the point where XRP is shunned.
If you look at how we generally solve problems in the world, the idea that the untrusted general public should be involved as a matter of principle is ludicrous, because that requires significant defenses against bad actors at multiple levels.
Bitcoin didn't even solve this problem, it just raised the economic barrier for bad actors to cause trouble. In practice, many smaller cryptocurrencies are highly vulnerable to 51% attacks, but even Bitcoin mining power is highly centralized to a few companies.
I think the way XRP or Libra solve things (in principle) has very strong arguments going for it, but they are pragmatic, not idealistic. I haven't heard any good arguments on how the way Bitcoin solves things is so beneficial that it becomes a worthwhile tradeoff. I don't see why it should be the defining factor on what is or isn't considered a cryptocurrency.
Ripple (or rather XRP, which I referred to as "Ripple") is widely referred to as cryptocurrency. It uses a distributed ledger and cryptography, like a cryptocurrency. It is traded on cryptocurrency exchanges and can be sent/received like a cryptocurrency (requiring no account registration like Paypal). Also, like most cryptocurrency it is backed by nothing and its price fluctuates and moves along with broader cryptocurrency market trends. For most intents and purposes, it is a cryptocurrency.
Of course one can make the distinction that a "true" cryptocurrency should be fully decentralized, but that's besides my point.