Rosh,
1: I agree with this point.
2: I possibly agree with some of this, but I probably wouldn’t word it so strongly.
3: I disagree with this. The Tzemach Tzedek says that shaving with scissors is deoraisa, and trimming is a safek deoraisa.
He is generally a yochid in this matter. He makes it clear in his teshuva that this against the opinion of Shulchan Aruch.
I agree that the Tzemach Tzedek is a very very great and holy yochid, and being that he is one of my holy rabbeim I accept all of his psokim, and I would love if the rest of the world followed suit, but I wouldn’t call him a rabim.
It is possible that majority of poskim prohibit shaving and trimming (albeit not medoraisa) as can be seen from the sefer Hadras Ponim Zokon, but I wouldn’t say that everyone is obligated to follow them because of yochid and rabim.
It may be very desirable to have a beard due to the overwhelming majority of poskim who encourage it, as well as other important maalos of beard, but I wouldn’t say it’s an obligation IF someone follows a rov who allows trimming.
I would agree however that it is wrong when people play two sides on which rabbanim they use. Some people might accept Rav Shach as daas Torah who must be followed by all of klal Yisroel in regard to Chabad (even though Reb Moshe openly disagreed with him, as can be seen in my post in a different thread) yet when it comes to beards they are meikel like Reb Moshe (when Rav Shach wrote that it is ossur to be meikel and use any type of electric shaver).
Obviously, this hypocrisy does not apply to someone who is against Chabad for his own logical reasons, instead of claiming that he’s just following “daas Torah”.