Catholics work harder than most Christians to keep Holy Communion pure of wicked leaven, as Paul teaches the Church to do. Any misunderstanding seems to be out of wanting to err on the side of keeping Communion pure. The Lord died for our sins, but that doesn't mean that we can sin with impunity, and be welcome to receive Holy Communion too. :nono:
The Catholic college of bishops are Jesus' authorized teachers of faith, and of morals. The Trinity is what Jesus wants us to believe.
The most important thing is that He is risen.