It's not easy accepting a 4-3 loss -- especially not against a mid-table side like Bournemouth and less so if your team was winning 3-1 with 15 minutes remaining.
Liverpool suffered a seismic shock on Sunday. Had it been part of a season-long pattern, then acceptance might be easier. But the Reds hadn't lost a match for 105 days. Defeat was a bolt from the blue.
Rationalisation of the result stemmed from that fact. Strange games can happen, and even great sides will lose matches they have dominated.