hi Eli,
I continue to find this discussion very interesting, and you raise once again important issues.
Regarding what you call the "Catholic attitude." The Catholic Church invites all people to partake of the Eucharist, and we long to arrive at this fullness of communion where we can share at the Lord's table together. So it's not a question of "forbidding" Protestants to partake of it.
Do the Scriptures themselves not warn how "not discerning the Lord's Body" in partaking of communion brings judgment upon the person who receives (1 Cor 11:29)?
We WANT our separated brethren to partake of it, but the Eucharist is the sign of FULL unity between believers, and so to want to have the Eucharist without committing oneself to the Catholic faith is, well, sort of like wanting to have sex without marriage: it is wanting the benefit and privilege without embracing the full commitment of faith, trust and obedience that the sacrament requires.
A few years ago, as an evangelical believer, I stood before the same decision. The result is that I am now Catholic. This shows you what I think is the right thing to do. The Lord did not found a collection of denominations where each one just decides what he wants to believe, or receives the Catholic Eucharist while playing "pick and choose" of what Catholic doctrines he wants to believe - and the disunity of denominationalism remains. He founded ONE Church, united in her faith and worship and in communion with Peter and the apostles (and their successors). So the invitation is extended to all to partake of the Eucharist through coming into full communion with the One, Holy, Catholic and Apostolic Church.
As expressed by the US conference of bishops:
Because Catholics believe that the celebration of the Eucharist is a sign of the reality of the oneness of faith, life, and worship, members of those churches with whom we are not yet fully united are ordinarily not admitted to Holy Communion. Eucharistic sharing in exceptional circumstances by other Christians requires permission according to the directives of the diocesan bishop and the provisions of canon law.
And so exceptions can be made only in "exceptional circumstances" :
When, in the Ordinary's (bishop's) judgment, a grave necessity arises, Catholic ministers may give the sacraments of Eucharist, Penance, and Anointing of the Sick to other Christians not in full communion with the Catholic Church, who ask for them of their own will, provided they give evidence of holding the Catholic faith regarding these sacraments and possess the required dispositions. (Catechism of the Catholic Church, 1401).
This is not a question of "opinion." The faith of the Church is clear. In some cases, bishops can make dispensations and give the sacraments to non-Catholics, and priests can do the same in cases of "grave necessity" (e.g. when a person is in danger of death). But any priest who does this casually is violating his own faith, because this encourages relativism and indifferentism (i.e. that one can just receive the Eucharist while believing whatever one wants).
Regarding your 3rd point, of course God doesn't compromise on anything. You surely remember that Protestantism did not exist for the first 1,500 years of the Church. It is not God but rather the Protestants who have compromised by breaking the unity of the Church and throwing away the priesthood and the Eucharist! This is surely not the fault of Protestants today (and the original Protestants also had some legitimate grounds for calling for reform). And yes, Protestant believers certainly share in a good measure of the life of Christ. But the solution is not to continue with the divisive denominationalism but to return to unity with the chair of Peter, to apostolic succession, and to a common faith and sharing in the Lord's Body and Blood.
I realize this is not very politically correct, but this is what the Church believes.
See also:
http://www.ewtn.com/expert/answers/intercommunion.htm
http://www.usccb.org/liturgy/q&a/mass/communion.shtml
Ariel
“God whispers to us in our pleasures, speaks to us in our conscience, but shouts in our pains: It is His megaphone to rouse a deaf world” C.S. Lewis