Separation of concerns at the OS level involves the creation of shared DLLs, and people complaining about bloat inevitably complain about the many megabytes of DLL files that the simplest program needs nowadays, even if it only uses a vanishing fraction of them. People slinging bloat accusations around seem to want a program in which every byte loaded from the disk is executed with high frequency or something.

In my opinion, you're totally correct. This is part of the reason I'm not very sympathetic to the bloat argument. The megabytes of libraries are there for good reasons.