It sounds like they're doing what people want. People seem to be ascribing a lot of mal-intent to actions that don't seem malicious to me.

> completely exposes your printer by removing existing access controls

If these printers are in LAN-only mode and you want to point 3rd-party software at them, don't you kind of expect the existing access controls (which are probably at least in part tied to cloud services) to be removed? Behind a LAN with developer mode on, you're generally going to (1) not be exposed to the internet anyway, and (2) probably know what you're doing and would be implementing access controls yourself anyway.

If you want a completely open (hardware and software) 3D printer, don't get a Bambu Lab machine I guess? A big part of the value of their printers is that they've managed to make everything so seamless. Some of that relies on a somewhat closed ecosystem. They're the Apple of 3D printers, but everyone keeps expecting them to be the Linux, just because their slicer (or parts of it anyway) is open-source. If openness is more important to you than those conveniences, go with a different brand. It's a good thing we have choices as consumers :)