Here’s a quote:
Preferring the ferial office over the saint’s feast. Dom Guéranger goes on to describe the moves of the Jansenists as follows: “The calendar would then be purged, and the aim, acknowledged by Grancolas (1727) and his accomplices, would be to make the clergy prefer the ferial office to that of the saints. What a pitiful spectacle! To see the putrid principles of Calvinism, so vulgarly opposed to those of the Holy See, which for two centuries has not ceased fortifying the Church’s calendar with the inclusion’ of new protectors, penetrate into our churches!”
John XXIII totally suppressed ten feasts from the calendar (eleven in Italy with the feast of Our Lady of Loreto), reduced 29 feasts of simple rank and nine of more elevated rank to mere commemorations, thus causing the ferial office to take precedence. He suppressed almost all the octaves and vigils, and replaced another 24 saints' days with the ferial office. Finally, with the new rules for Lent, the feasts of another nine saints, officially in the calendar, are never celebrated. In sum, the reform of John XXIII purged about 81 or 82 feasts of saints, sacrificing them to "Calvinist principles."
Dom Gueranger also notes that the Jansenists suppressed the feasts of the saints in Lent. John XXIII did the same, keeping only the feasts of first and second class. Since they always fall during Lent, the feasts of St. Thomas Aquinas, St. Gregory the Great. St. Benedict, St. Patrick, and St. Gabriel the Archangel would never be celebrated.
I won’t post the links, because I don’t like any of the sites (for instance, this site I got this from seems to think Bl. John XXIII was a Jansenist), but you can find them by searching on “St. Patrick Bugnini calendar” in Yahoo! or Google.