You are not going to get me to believe that it is slow. Not with that hull design. I think they just aren't telling us everything.
I guess it wouldn’t make sense to broadcast exactly when the marines might be landing.
Well, 24 knots is about 28 miles per hour. Listed top speed is 24 knots, so she will probably do 28-30 when necessary...in a pinch, maybe a little more.
I know that the nuclear carriers, which are listed at 30+ will do over 45 for short periods if necessary...like to avoid a torpedo...or outrun it.
They will flat leave their escorts behind if they have to, because all of them are non-nuclear these days and they are listed at 30 knots but can max out at 38 or so.