He is of course quite correct. However, 'objectively sinful' does not necessarily mean 'in a state of mortal sin.'
So if one is divorced and 'remarried', and having marital relations in the new relationship, one is certainly in a situation that is objectively sinful. However, if one is subject to duress, for example (and that might be the duress of a partner threatening to abandon oneself and one's children - or even to harm them) then one might well not be in a state of mortal sin, for which free consent is a condition.
In which case, the damage to one's soul is less; and perseverance in attending Mass (and humility and obedience in not presenting for Holy Communion) are surely likely to be of significant spiritual benefit.
It also means, of course, that we should not assume that because someone is in an irregular situation, he or she is in a state of mortal sin. Indeed, we are expressly forbidden from making such a judgement.
Nonetheless, the Church is correct in her requirement that those living in such an irregular state of life do not present for Holy Communion, not least because of the risk of grave scandal (and there are other reasons, too, such as the problems of being judge in one's own case...)
But as I have blogged before, we should not underestimate the love and compassion of God.