I don't think anyone is disputing closing once and doing all the necessary work.
The thing that people are pointing out is that they're doing that on SE AND Batwing AND DD (which has other issues) AND Scooby all at the same time, with a lot of unplanned stoppages/late openings/closed seats on GL, Rivals, RR, and WWF. There have been several days where MW were charging $110 single day entry for people to watch HWSD2, and see Batman showcase because every single adult ride has been closed, as well as Road Runner - meaning there was not a single roller coaster or thrill ride operational.
That is an unacceptable situation to be in and is 100% due to the park's management failing to invest adequately in the maintenance of their rides, plan maintenance schedules properly, and replace defunct rides in a timely manner when it is clear that they've reached the end of their lifespan (SD, AA, DD).
But also due to the types of rides and attractions they operate. A simulator ride like Batman could operate even if one or two simulators failed - just at reduced capacity. The Movie Magic show could still operate if one of the show elements failed, other areas of the show could be padded out and the host could still explain how things work with other demonstrations. It also means that annual maintenance can occur on part of the attraction while it is still operational, reducing the amount of time it would need to be closed.
It is also apparent that there are management issues from staff attitudes toward visitors. Staff are not friendly, none of them want to be there, and replies to customer complaints on social media have shown absolute contempt for visitors that just wanted a fun day out with their family. Compare that with DW, where they acknowledge they are in a state of transition, they know most of the park is a construction zone, but the staff are engaging, friendly, courteous, and genuinely want to see people enjoying themselves. I visited DW for the first time since 2015 the other week and the staff were the single most memorable part of my day. The staff issue at MW is what really indicates this is a top-down problem because the front line workers are unsupported and have no power to fix the situation for unhappy visitors.
A theme park is a retail business, a service industry business, an art/design and performance business and a heavy machinery business. Movie World was once the stand out performer in Australia for all of these, but it's fallen behind in all of them and completely bungled the last one.
People are rightfully pointing out that 2 month closures should be unnecessary, and planned overlapping closures are just bad management. But 2 month closures when you've got so many other closures - planned or temporary - happening in the park to the point that people are paying full price entry and cannot go on a single ride, is what most people in this thread are complaining about.
Yes, DW have some extended closures for various reasons, but the difference is in the broader context of the park's offerings and operations.