For sure, subject matter is a question of taste.
I think it’s a matter of perspective too. When I first heard about some of the darker Nordic larps, like Europa which was set in a refugee transfer station, I thought that they had a weird idea of fun. I thought larp was only useful for having fun (a simplification of my views, but something like that). After reading a bit more about the player experience, I began to mentally wander down the “maybe larp can be used for other things than fun too” corridor. To make a movie analogy, a person who likes romantic comedy movies and thinks that movies should be about escapism can re-orient their views and grow to like movies of harsh realism too, for different reasons. But there’s no particular need for anyone to do so, it’s just an option.
Some techniques are better for stealing than others. I used to suggest stealing improv techniques for larp, but in retrospect I think some of them were inappropriate. Like the “yes, and…” stuff, where you basically cooperate to create shared backstory with characters through play. This works in improv and works in Jeepform because everyone can hear what everyone says and use it, and there’s no organiser-created backstory to conflict with. Not so appropriate in most larp.
I think the main objection some people might have to Jeepform is the story focus. The creation of a story is the point of Jeepform play, the players don’t really own the characters so much as they cooperate to create the story. Jeepform is not about experiencing being the character, so it’s okay if you know things the character wouldn’t. This ties in perfectly with techniques like Transparency (all the players know everything that’s happening, so that they can all help to build story, nothing is hidden), making some Jeepform techniques more of a bundled package than they might first appear. But transparency is impossible in most larps because the players know character and setting secrets, and because play is distributed in space and time. Other techniques, like the camera aside, work very well to support the Jeepform story-focus but are more transferable as you point out.