

Proprietary software is proprietary no matter how “nice” it is. It should not be advertised in FOSS communities and falsely presenting it as “FOSS adjacent” is harmful to the movement IMO.
There are many places so called “good proprietary apps” can be promoted and discussed.
It’s the free software movement, though - the four freedoms are literally the cornerstone of the movement. They’re not simply a “nice to have” they’re the bare minimum of what we should ask for. If we promote non-free “alternatives” we are saying that these basic freedoms are not an expectation, but are optional and negotiable - we are moving the message away from the four freedoms and towards “evil” proprietary applications, while making exceptions for the “lesser evil” ones.
When I say Obsidian is non-free I am not saying Obsidian is evil or you are not allowed to use it. As non-free apps go Obsidian is probably one of the least-worst, as you and many others point out it is just a markdown editor so there is no vendor lock in or weird proprietary format. I am simply saying, this is a movement focused on “the four freedoms” and Obsidian does not meet those four very basic criteria.