B. Forsaking the assembly - ἐγκαταλείπω - to abandon, desert, to leave in straits. This is a barometer for a spiritual condition. It is a reflection of an attitude.
Barometer? If a Christian forsakes the assembly, it does indicate carnality; but conversely, there must be millions of Sunday-go-to-meeting"Christians," hypocrites who are also carnal. A person who trusts the Lord Jesus as Savior (not as mere chance-giver), a person who trusts the Savior as only & sufficient Savior, not in works, indeed ought not to forsake the assembly. And it is an important admonition, immediately followed by a passage that threatens chastisement for willful sin.
But that laundry list you posted is not connected specifically, neither do you have any proof that neglecting the assembly is trampling the blood of the Lord Jesus underfoot. That is largely just you saying things.
As bad as it is for a Christian to neglect church attendance, "church attendance" can also be quite bad for a pretender. A pretender professes belief, gets "baptized," and joins a church instead of getting saved. Then he proceeds to act religious and imagines himself a Christian. It is like getting the cow pox to prevent you from getting the small pox; it is an inoculation vs salvation. There are the religious who will hear someday, "Depart from Me; I never knew you."