I have to agree with @paf@jlai.lu on this. I’d much rather have those models as part of the ecosystem than not. I do think part of the 3d printing hobby is learning to look at a model and recognize what can be printed on what type of printer, where supports are needed and where modifications may need to be made. For example, I recently purchased a model through TitanCraft. And the models they create are clearly designed with a resin printer in mind. they have some small features which are difficult or impossible to print on an FDM printer. While I knew that mini-figure models can be challenging on FDM, I went ahead with the purchase anyway. And the resulting min-fig’s staff was so thin my printer just couldn’t print it cleanly. I had to load the STL into Blender and spend an hour or two separating the staff out from the rest of the model and then I thickened it considerably. Sure, the haft of the shaft is a bit thick for the proportions of the model, but not too bad.

I make a similar evaluation of stuff I see on the various model sharing sites, before I try to print it. Does it need supports? Are some of the details going to be very hard or impossible for my printer to make? Should I split the model? And, while I am pretty crap at Blender, I may consider doing some simple edits to make a model easier to print and/or make changes I want. For example, I liked these ghosts but didn’t care for the spring and just wanted them hollow so I could stuff a UV LED inside them. With glow in the dark PLA, these look neat at night. So, I beat my head against Blender until I had them how I wanted them.

So, I wouldn’t want to stifle other peoples’ creativity. Let them create and enjoy the fact that people are willing to create and release this stuff for you to print. If it doesn’t work out, fix it and re-release it.