As a long time reader of manga, and a long-time scanlator myself, it's amazing how many people take for granted how easily it is to read scanlations nowadays, either on MD or some other aggregate. 15 years ago, when many of MD's detractors ITT were either very young or not even born yet, you couldn't even read the manga online. You had to download it, either from an aggregator like StopTazmo or NarutoFan (which was for profit, and is essentially what aggregators other than MD do today), or download them directly from the scanlators' websites or IRC channel. If you haven't already, check out Inside Scanlation's history page, specifically
https://www.insidescanlation.com/history/history-3-4.html which details the rise of online readers which predated MD by about a decade.
In other words, what is happening is that some scanlators who signed on to this exodus want things to go back to the good ol' days when it was harder for readers to actually read manga. As I said, aggregators have always been a thing, and will always be a thing, so pulling out from the only legitimately
not-for-profit aggregator on the internet is really only benefiting the pirate aggregators and ultimately hurting the readers.
Readers simply do not care where they read manga, but they do care how easy it is to read manga. You can talk about reader loyalty all you want, but most readers aren't even loyal to the groups they follow. I know, since I've had series I've worked on snipped right from under me, and most people are appreciative that they can read a chapter any way they can, even if it wouldn't quite be up to the same quality as what other groups can do.
Besides, even if MD went legit (which is highly unlikely, going by the comments from the admins), that's not to say something like MD wouldn't pop up sometime later. Back when Batoto died a year and a half ago, there was a scramble from several people talking about doing Batoto's successor. Holo and his team just did it faster and better than anyone else back then. So if MD went legit and stopped hosting scanlations, there will probably be a successor to MD to fill that gap, but it would inevitably be far inferior to MD, at least from what I've seen historically. MD is, in essence, the head of gold of Daniel's statue, so I would suggest to be a little more appreciative from a reader's perspective, which obviously makes up most of the traffic on this site.