Why someone would get into FOSS development and then get upset when someone exercises their rights to build from source and distribute binaries is baffling to me.

This happens at an alarming rate within the video game emulation community. Many projects (including MAME) have openly expressed deep disdain for any forks existing at all. It's like they think any difference a fork has is a negative thing and then aggressively attack that... as if there is only one way to write software. Some projects have even stopped upstream development entirely, or closed the source or changed their license... just over forks. License violations (including GPL as well as non-commercial ones) are also rampant there.