How a business chooses to manage it's operating hours is up to them. Everything listed in the post above is a matter that can be checked with a little research by the guest before arriving. The park has made their hours very clear on website and socials. Night market sends out emails every week with what's on, or if they're closed. When they have private events on, they publish that for weeks in advance of the date.
I took my family to an activity over christmas. we arrived early, hoping to beat the crowds, only to discover that although the place it was at opened at 9 - along with every other service provider in the complex, this one particular facility didn't open until 10:30. I was a little annoyed - why doesn't this operator open at the same time as everyone else? but then I realised that the doors (and the website, and google) clearly showed what their trading hours were. I simply hadn't bothered to check and assumed this place was like all the others in the same location. the fault was mine.
I understand dreamworld operating lower hours midweek outside of peak. if i were a local, i'd be a little annoyed - and personally I think they're missing out on the after school traffic - but i've also seen the after school population at Movie World and wondered how they afford the staffing bill - because most of those after school visitors weren't there to buy expensive ice cream. they were there to ride on an annual pass that cost nothing for a post-school visit. So i'm not sure if the economics work out to stay open for the possible ice cream purchases that probably won't come.
As for visiting the waterpark - i'm not privy to their finances, but again, you want them to be open for a 7 hour trading day for the possibility of capturing post-school trade for the last 2 hours. what a waste of 5 hours of labour (plus the pre-opening labour required). They've got the numbers, and they've decided it's not viable.
And this has been repeated to you so many times it's becoming a turnstile-level issue.
Restaurant opening times are clearly posted. Nobody would have assumed it was open at night prior to this step, and they've been very clear about saturday openings and providing a booking link. bookings won't be possible on friday, so that should be a big red fucking hint it isn't open. if you turn up on friday to eat at janes without a reservation - that's really on you.
All of these situations are fanciful inventions in your own mind and have no connection with reality. I'm not seeing reviews posted to Dreamworld's various online presences complaining about short hours or closed waterparks. i'm seeing reviews of how great the experience was.
Don't even start me on how the company with the 7-hour-trade-7-days-per-week parks and the non-seasonal waterpark is performing in the guest reviews space... because it isn't pretty.