From the translation and explanation of Srīmad-Bhāgavatam 1.8.5 here:
The clever Duryodhana and his party cunningly usurped the kingdom of Yudhiṣṭhira, who had no enemy. By the grace of the Lord, the recovery was executed, and the unscrupulous kings who joined with Duryodhana were killed by Him. Others also died, their duration of life having decreased for their rough handling of the hair of Queen Draupadī.
In the glorious days, or before the advent of the Age of Kali, the brāhmaṇas, the cows, the women, the children and the old men were properly given protection....
The killing of the above-mentioned innocent creatures is totally forbidden because even by insulting them one loses one’s duration of life.
In the Age of Kali they are not properly protected, and therefore the duration of life of the present generation has shortened considerably.
I believe the author here has incorrectly extrapolated the specific case, that of a few miscreants' rough handling of Draupadi, and applied it to the entire humanity in Kaliyuga. He's hinting that the primary reason, life expectancy of present generation is considerably less than previous Yugas is because no person currently does a good job of protecting those five beings [brāhmaṇas, cows, women, children and old men] or is he correct in his interpretation?
Few answers that attest to longer life-spans of characters from earlier Yugas can be found here: