Ultimately, on Good Friday the Church mourns the Real Loss, rather than celebrating the Real Presence.
Consequently, it is fitting that the faithful likewise mourn, and not receive the Communion of the unbloody sacrifice on the same day that Our Lord gave us his bloody sacrifice.
For some interesting discussion of this issue, see here: https://theradtrad.blogspot.com/2016/01/communion-on-good-friday.html
Yes, I understand. Part of me would want to have the intimate union of Holy Communion to join as closely as possible to Our Lord while commemorating His Passion, but then Our Lord Himself suffered the sense of total abandonment by God the Father. So there are probably pros and cons to both. I feel that I could be more closely united with Him in His Passion by receiving Holy Communion, but then the sense of being deprived of God would more closely resemble what Our Lord Himself experienced.
With regard to "unbloody", the reason that it's unbloody is because Our Lord is alive and is in fact no longer going through his bloody Passion. That's where the ambiguity comes from for me. Just as the sacrifice is unbloody, can't we partake of it even while commemorating the bloody sacrifice of the past? I think we could in theory, and I go back and forth on this particular question. Is there enough benefit to souls from being deprived of Holy Communion to offset the loss of the graces that could be had from actually receiving Holy Communion?
In the Eastern Rites, the faithful can partake of Holy Communion at Masses of the Pre-Sanctified, but on Good Friday there's no Mass of Pre-Sanctified either, just some Psalms and a Liturgy involving the Burial Cloth of Christ. I actually find it lacking that there's no Liturgy there associated with Our Lord's Crucifixion and Passion either, just the aftermath, the Burial.