The confusion about whether people in mortal sin can lawfully receive communion is related to communion in the hand because communion in the hand arbitrarily makes every communicant habitually an extraordinary minister of holy communion, reducing the dignity of that role to a banality.
Communion in hand and the ubiquitous "communion cup", which amounts to an even sloppier and less reverent version of same, even to the point of disgust, are today more than ever a litmus test against traditional clergy, used by otherwise seemingly "moderate" bishops and seminary formation teams to discourage and eliminate traditional zeal and piety in the ranks of young clerics.
There are bishops and vocations directors who regularly recommend their priests and candidates for the priesthood who openly admit that their conscience is violated in this matter, that they should consider a vocation to the Fraternity of Saint Peter (viz. conform or leave).
There's a pastoral model for you, when people have Catholic zeal send them away, there is no room for them in the life of the Parish.
I say that if communion in the hand does not bother your conscience too much, then communion of unrepentant manifest mortal sinners will be easier for you to accept. it's a slippery slope.
The Germans were the first to force the sacrilege of communion in the hand, in open disobedience, and they are the first to force the manifest sacrilege of communion for adulterers. The militant homosexualists won't be far behind in that sacrilegious communion line (that's another problem: communion at the communion rail all but eliminates the unnecessary inconveniences of the communion line and who's receiving and who isn't, etc. and the reception rush). At most suburban parishes the communion rush is a bedlam of beehive activity completely antithetical to the liturgy with an army of "ministers" and an army of ushers and an army of communicants in battle formation all going at a quick clip which more resembles a battle field mass than the mass of the ages.
Chaos by design is the model of modern liturgical practice, adulterer communion should fit right in to complete the confusion. It would be liturgical invention. The liturgy is erroneously deemed what we make it to be rather than what we receive from God and from the Tradition of His Church. And communion becomes self-ministry.
We banalize the reception of Holy Communion to such a point that anybody can handle it, so now everybody demands to do so, in whatever condition. It's part of the problem of making the handling of communion a presumed right of all.