What I find puzzling is that many Catholics concede that Protestant Christians CAN be saved and are genuine Christians, while being without that core teaching of the absolute necessity of receiving the Eucharist for salvation.

I’d like a lurking Catholic to explain this. Are these ecumenical Catholics just being devious, or do they not believe Catholic doctrine?

I'm not a "Lurking Catholic" but the statement seems to be contrary to the Ex Cathedra statements of the Pope

http://www.onetruecatholicfaith.com/Roman-Catholic-Articles.php?id=443&title=1.+The+Chair+of+St.+Peter+on+Outside+the+Catholic+Church+There+is+No+Salvation&category=Outside+the+Catholic+Church+there+is+no+Salvation&page=1

Pope Boniface VIII, Unam Sanctam, Nov. 18, 1302, ex cathedra:

“With Faith urging us we are forced to believe and to hold the one, holy, Catholic Church and that, apostolic, and we firmly believe and simply confess this Church outside of which there is no salvation nor remission of sin… Furthermore, we declare, say, define, and proclaim to every human creature that they by absolute necessity for salvation are entirely subject to the Roman Pontiff.”

Interesting. So, because subsequent popes have said that non-Catholics can go to heaven, salvation, they were spouting heresy, as many Catholics do today?

...this Church outside of which there is no salvation nor remission of sin...