Translation:Freedom is under the king's protection.
I think the point here is that freedom is upheld by the king rather than just exists; but it's all rather "grey" and your sentence, like many others, is a reasonable representation in English, but simply not in DL's database. There's also an element of idiom in the German Sentence which should give us licence to offer something idiomatic in English as a translation. Yours works for me.
More than one definition of ‘stehen’ in the Cambridge Dictionary (link) lists ‘to be’ as a possible translation. The most fitting in this context, I believe, is number 6 [emphasis in the original]:
(in Zustand, Situation) sich in einem bestimmten Zustand, einer Situation befinden
At any rate, while it may be hard to find a dictionary listing ‘to be’ under the translations for ‘stehen’ (mostly, I think, because it gives no information about its meaning and/or implicatures), you will find that, since German is almost fixated on giving details about positioning and movement of things, ‘to be’ is indeed a very common translation for ‘stehen’ (along with ‘liegen’ and ‘hängen’) especially when referring to where something or someone is.
This point has been argued above, but it boils down to idiom: i.e. what the natives do, and, what's in DL's database ."Lies", "rests" and "exists" all work for me in the English translation and I'm sure that you would still be understood if you used equivalents in German: but as Ly_Mar managed to convince me earlier, "stehen" is a pretty good idiomatic option in German and there's something resolute about "standing" against those who oppose freedom.