To simplify, Yoga means union (with the existence) and the word has sacred/divine connotations. So using it for all sorts of things like say naked yoga etc and disregarding the sanskrit name for the yogasanas and calling it things like downward dog pose etc is uncomfortable. Hopefully the yogasana practicioners will get curious and go deeper into the philosophy and mindset of the Hindu philosophy.
If anyone wants the full Yoga experience I recommend organisations like ISHA Yoga Foundation.
Btw regarding open source software comparisons, people either want to force the original repo into drastically changing the rules of contribution or instead of forking it and acknowledging the original project they just want to copy it with same name but do their own thing (for eg mindfulness vs meditation)