Tradovate is not a prop firm. It’s a trading platform (and a very good one).
Almost all the futures prop firms offer the Tradovate platform among the choices available for their customers to use. (Free).
The forex/CFD prop firms don’t offer Tradovate because it’s a futures trading platform and isn’t used for forex/CFDs.
The Tradovate company (which is owned by another company called NinjaTrader) is also a brokerage in its own right, and they have their own independent customers who trade their own futures accounts too, as well as the futures prop firms’ customers who are using Tradovate because so many futures prop firms also happen to use it.
I hope that clarifies it! 