Yeah, I think I'm with ya on this.
As far as the form goes, I guess I think especially in Tai Chi sometimes a teacher will give his student the nod to teach certain aspects of the art, even if full understanding of the complete art is still lacking. The teacher might say, "OK, you seem to understand the Chen 24 Posture Form pretty well, you can teach THAT to some students if you like." But I think there is an implied limit on that, and the 24 Form is far from the complete Chen system. I personally don't consider this person a Chen Tai Chi Sifu. He's still very much a student himself, with very limited teaching authority.
I sometimes see people list their resume online, and it seems to go on forever, you gotta keep scrolling down and down and down to see it all. They like to list every underbelt rank ever achieved in any system, every seminar they ever took that is even vaguely connected to martial arts, even tho it never lead to anything further, and every trophy they ever won in any tournament, and every famous person they ever shook hands with. It seems like listing every form and every partial art they have ever encountered is just resume padding.
I also understand what you are saying about being called "sifu". I've been training with my sifu for just about 10 years now, and about 2 years ago or so he asked me to begin leading some of the students thru some basic tai chi sword work. I think some of the students have begun to see me as a sifu in my own right, or at least an assistant sifu, but I don't feel like I merit that kind of title yet. I'm just a student struggling with the sword myself, and teaching it helps me focus on the details, and gives my sifu another opportunity to guide me as well when he makes corrections.
Ah well. It's all in how you present yourself. I think some people want to grasp at the authority and dignity and status that being a teacher with high rank seems to imply. I'm really in no hurry to make such a claim.