@Angelo Farina , not everyone can wiggle their ears or move their scalps. I can do it and I do not even know, why. BTV and Frenzel are about isolating and controlling the muscles around soft palate. Only small percentage of people will be able to do it out of the bat as only few people can wiggle their ears. The rest will have to do a lot of practice until they can learn and this is not trivial. If you do not teach valsalva or present it as a dangerous option and rule it out, you already increased the risk of an injury. Valsalva does not require any special muscle control or even much practice. You cannot do Frenzel with open mouth it is because you have not practiced enough and you do not belong to the minority group who developed the skill naturally, that is all.
I agree, but it is a matter of priority. To my students I always presented a number of equalization methos, including Valsalva. But the order I always used is:
1) BTV, as this is what I did always use, and I think is the best. 1/5 of the students are done with it.
2) Marcante-Odaglia. A lot of people already use it, mostly thinking it is Valsalva (possibly even you). Some other think it is Frenzel. But it does not have the drawbacks of Valsalva, nor those of pure Frenzel. Let say that another 1/5 of the students can perform easily this method. All the others could (as it is much easier than Frenzel), but it requires doing exercises, so let's leave the remaining 3/5 for now.
3) Toynbee. Swallowing is easy and effective for a small number of students. We can assume a third 1/5 of the students are done immediately with Toynbee.
4) Valsalva. Here we are addressing the remaining 2/5 of students, those with more problems, who cannot manage any of the previous 3 methods without some specific training. Valsalva is simple, and is immediately succesfull for half of these remaining students.
5) the last group of 1/5 of students still have problems equalizing, due to a combination of factors.These include narrow tubes, chronical inflammation (smokers), anxiety, lack of control, etc.
These students are not done in one lesson, they require specific training lasting as much as 10 one-hour lessons in a deep swimming pool. For these students often it is necessary to resort to some of the most advanced techniques, which combine a basic Valsalva with something else (Lowry, for example).
As you see I did not include Frenzel in the list. I think Frenzel is worth to be taught only to deep free divers, no need of Frenzel for scuba divers, who have plenty of time descending slowly and equalizing at will.
In conclusion, Valsalva is one of the many methods available. It should never be the first choice, in my opinion, as several other methods are available, which are both easier and safer for a minority of students.
Valsalva should not be demonised, indeed: it can be the right method for the largest group of students.
But I find barely stupid to ask a student who can succesfully equalise using BTV, Marcante-Odaglia or Toynbee to use Valsalva.
Of course a Valsalva done properly is just marginally more dangerous than other methods, and definitely less dangerous than not getting proper equalization.
So it is just matter of presenting the various methods in a reasonable order, and then let each student to become proficient in the method which works better for him/her, including Valsalva.
What I do not like is presenting Valsalva as the first, better method for everyone.