This is kinda innaccurate as many faithful Catholics choose to honor Christ by expressing belief in His presence in this way.
This does not distinguish Sedevacantists at all as there are millions of faithful Catholics who still honor Christ by practicing the faith with extra devotion and respect.
Just because someone fasts longer than the 1 hour recommended does not make them unfaithful, just because someone prefers to receive Christ kneeling does not make them unfaithful, just because someone prefers to only allow the Priest to handle the Blessed Sacrament does not make them unfaithful, this just shows an extra devotion, just like saying the rosary daily does not make one unfaithful. It is insulting to those Catholics who practice their faith courageously and more faithfully than people who casually practice it. This does not take away from those who receive in the hand, fast for exactly one hour, or women who do not cover their heads, we should focus on our own holiness, not on comparisons.
If I misunderstood you, please tell me and forgive me, as many faithful Catholics practice the faith as it seems you have described.
Now on the other hand Sedevacantistism is distinctive in that it claims that our Holy Father is not valid, an imposter. They would hold that either there is no Pope or another one existing, based upon theories of apostacy and validity of ordination. They have rejected the unity of Christ as evidenced by submission to Him and His Church. They have rejected the unity of Peter and replaced it with either a replacement or an empty spot which they fill with their own personal interpretation of the faith. The Mass is just a symptom they use not what distinguished them. We can all agree that there have been many scandelous Masses that people can use to attack the faith with.
Now the Pope can make mistakes and even behave in ways that are scandelous, that does not make him an imposter. Peter was rebuked by Paul, and was still infallible in his teaching. The Pope might make a mistake or improperly represent the truth, he is a man who has a huge responsibility. We should pray for our Holy Father as many times it is not his fault at all. There are some who misrepresent his actions, who plan ways to misrepresent his intentions and shake the faith of people.
So yes there are ways to pick apart a persons actions or words and show them in the worst possible light. Imagine if you were in the spotlight and people had access to countless images, videos and writings of yours (lets say you spent a lifetime publically communicating about the faith and it was recorded), would they be able to present them in a negative way to present you as denying the faith of Christ?
God Bless
Scylla