My first playthrough of this game was a weird one. It had more cuts than RE2R but somehow the cuts to RE2R irked me more. It boiled down to me having a bigger connection to the original Resident Evil 2.
I enjoyed RE3R but I can't blame people for being annoyed. It is a great game no doubt but they completely missed the point of the original RE3 and that's why the reimagining fails in ways that RE2R's didn't. RE2R totally understood RE2 despite it cutting some elements out. RE3R feels like they took RE3 and missed the point on it and just redid it in a new way. To a person who is extremely into the original RE3 that could rustle some feathers.
I'll break down what they get wrong.
Raccoon City feels small
In the original game the city felt very interconnected. You can walk to the police station, walk to the hospital, walk to the park from the hospital, walk to the dead factory. Everything feels majorly connected.
In comparison, RE3R many times just teleports you to a major location using a cutscene. Doing this makes the world feel less connected and tiny. So in the end you have the demo section of the city which is great but limited and then a lot of linear paths till you teleport to the hospital which is a hub.
Even the intro rushes through events in the original game in a way that it makes every moment feel less meaningful. In the original Dario Russo felt like a character Jill was talking with for a while. In the remake you just barge in and have a brief convo with the stranger and leave. It's like they did a greatest hits of the OG's opening and just rattled them off in succession. It again makes Raccoon City feel small.
Nemesis was botched
I like how he looks in the remake but the remake kinda screws up the lead villain of the game in various ways. For one he doesn't kill a single stars member in the remake. For a monster that is supposed to be a threat to STARS, having him not kill Brad was a massive mistake. It establishes that he knows how to get the job done and you're next.
On top of that for whatever reason Nemesis doesn't feel like the persistent threat as he was in the original. I think he was used less and they made him turn into his beast form way too soon which cut him off from any other chase sequences. Those chase sequences being incredibly scripted didn't help the dynamics of it either. Whereas in the original much of his moments were unscripted moments where he can just pop up throughout the city.
Player Choice
I know some people don't like live selection but the idea of there being decisions that can be made ala Until Dawn really shook things up in an interesting way. RE3 was in essence a choose your adventure and it lead to different endings ( which the remake didn't have ). It didn't always make for vastly different changes but it made subsequent playthroughs more fun knowing you can change up your decision making and see the outcome of those decisions. So RE3 went from being a largely open and player driven experience to a very linear and player controlled experience.
Cuts
It goes without saying cutting the clock tower as a location was a mistake. For one the game greatly needed a fresh and different location. Going from the hospital to the lab felt kinda samey. So for them to cut Clock Tower and expand the hospital it felt like the wrong direction to take. The hospital was short in the original so it made sense to keep it limited in the remake. The Clock Tower visually allowed for a classic styled RE local to show up and also give some variety to what comes after it with the dead factory.
RE3R taking out locations that give more unique aesthetics and then pumping it with locations that didn't was one of it's biggest mistakes. Cutting Clock Tower, Town Hall, The Park, and even Dead Factory. Bringing in a Sewer, a giant building set piece you run up to fight a boss, expanding the hospital, and turning Dead Factory into another Nest just hurt the diversity of locations.
Also cutting the Grave Digger was a mistake. It wasn't a great battle in the original game but it could have been made into one. When you diminish the Nemesis and don't even have any other bosses to make up for it, it can be a let down.
Also shockingly RE3 had a decent amount of puzzles which felt like a complete afterthought in the remake.
Having said all that ......
RE3R does a fantastic job with characterization, files, and music. It's just a shame it got so much of the rest wrong. I like the game more than most but I totally sympathize with people who feel like it got screwed. I think people trying to pretend anyone who is critical of this game just wasn't a fan of the original RE3 to begin with isn't a fair criticism. I've recently grown to love RE3 OG a great deal. If anything RE3R had the opportunity to show people what they missed in RE3 OG since it's been so overlooked. Instead they botched that opportunity by making a lesser version.
Killer8
I think the reason people give RE3R more flack is for the reasons I stated above. RE2R and RE4R don't get the essence wrong. For the most part they knock it out of the park on what each game originally was. It just reimagines some ideas and omits some elements here and there. In RE4R's case it's such a big game that a few cuts don't stick out as much as RE3R which is an incredibly short game that could have used more content. Not to mention the thing you mentioned that got cut in RE4R has a good chance of being in some Ada DLC.