If I can analyze other singers with extreme accuracy it means I can diagnose advanced technique issues of future students. It also means that I have a handful of tricks up my sleeve for the nights where I don't have access to my high M1. Listening to people who are really good and trying to analyze what they're doing is helpful to me. It's how I spend ALL of my free-time and it makes sense for anyone trying to attain a high degree of proficiency to do the same!
I practice, read books, read research, analyze technique (including modes, M1 vs M2, phrasing, dynamics, choice of vibrato, etc.), it's all part of the package to becoming a master of the craft.
It's not that I'm annoyed by SLS techniques. They're interesting, the teachers are interesting. I want to dissect how they think without using their definitions so I can better understand more than just their technique; I want to know their mental frame.
Jeanette LoVetri writes in her blog about how there aren't many singers who attain a high degree of proficiency in both "pulling M1" and "mixing into M2." The two skills can often be diametrically opposed (though I'm in the process of learning both.) There's a certain degree of muscle memory attached to both techniques and moving from one to the other will often result in just an OK performance even by a great singer.
There are many singers who we can argue endlessly "M1 or M2?" and that's not really the point to me (sometimes I want to get another perspective so I can best replicate the technique, however.) You're not supposed to tell the difference! Someone who has done this for 10 years, you're not necessarily going to know the difference ESPECIALLY if you haven't trained your ear to do so. They have spent the last decade training their M2 to sound identical to M1; especially in a performance context where you can't just hit "replay" over and over you probably won't know. You can probably even fool ~some~ casting directors looking for a big "belt" in a musical theater audition.
My realization recently is part of the proficiency in their style is that their definitions had to be "altered." "Mix" to many contemporary operatic tenors with a high C5 in M1 does not mean a transition into M2. It means "mixed resonance" in M1. "Full voice" also doesn't mean M2. "Head voice" to males often doesn't mean M2, either. Go back to the renaissance, however, and you would find different definitions. I'm not saying one method is right or wrong in their definitions.. techincally EVERY method is wrong who uses definitions like "head" and "chest" which literally originate from the pre-scientific dark ages.
It was just interesting to realize recently that the difference in perspective is just a vague debate about semantics. Also interesting that most SLS singers aren't interested in learning or discussing M1/M2. I imagine that if they did learn what they were "actually" doing, where specifically they were "bridging," etc. that it could ruin the illusion necessarily to perform the skill at a high degree of proficiency.
Operatic sopranos and countertenors (both M2 mixers) often communicate a similar "confusion" in technique. Sopranos claiming to never use chest, countertenors claiming to never use head. They're both moving between M1 to M2; whatever their definition of "head" or "chest" is irreverent and quite silly.
Pavarotti, however, (M1 puller,) has made statements similar along the lines of saying tenors who use M2 to sing their high notes "aren't real tenors." Obviously I disagree with this, particularly in pop music.
Both sides have their own perspective, definitions, and illusions necessary in order to maintain their technique. This was an interesting discovery to me which explains much of the confusion I experienced in the past trying to "find the mix."