I am of two minds on this.
On the one hand, I can find nothing in Scripture that requires that Communion be conducted in church or be administered by a minister. The only admonitions I can find are that the believer examine himself/herself before partaking to insure that we are not partaking unworthily - that is with unrepented sin in our lives - and that when we partake in Communion, we do so in remembrance of Him.
On the other hand, if you want to call yourself Catholic, you should be willing to abide by the teachings of the Catholic Church. If you are not willing to do so, and are very public about it, then you should not be surprised when you are removed from the body of that organization.
Thread killer! ;-)
Excommunication is much more severe than mere removal from an organization.
Agreed on your second point.
To your first point, obviously Masses can be offered in people’s homes, outdoors, and in catacombs, so yes, that is not an absolute injunction. But Scripture doesn’t go into detail on the topic so it helps to also consult other reliable Christian writings of the time period.
Check this out, it’s an account of the Christian liturgy written by Justin Martyr around A.D. 150:
http://www.freerepublic.com/focus/f-religion/1763662/posts