The only holy day of obligation in the United States that is transferred as a rule to a Sunday is Ascension. The only dioceses that keep Ascension on the actual Thursday are: Boston, Hartford, New York, Newark, Omaha, and Philadelphia.
For January 1 and August 15, if these fall on a Saturday or Monday, the holy days are not transferred, nor abrogated; what the NO bishops decided in 1992 was simply to abrogate the obligation to attend Holy Mass.
To illustrate the difference: in the diocese of Honolulu, all canonical holy days of obligation for the US are abrogated except Christmas and Immaculate Conception.
To further illustrate, when Immaculate Conception falls on Saturday or Monday, the obligation to attend Mass has not been abrogated by the bishops. But if it falls on Sunday, the holy day is transferred to Monday, and the precept to attend Mass is abrogated. Hence there is still "technically" a holy day.
But remember that for every holy day of obligation (and Sunday), there are two obligations: 1) Mass attendance on the day of (in the NO, there is the novelty of anticipating the obligation the evening before); and 2) abstain from servile work that would hinder the worship due to God. These are distinct obligations although linked (resting is ordered to worship). Even without Mass attendance, worship is still possible but merely private and devotional.
Hence the US bishops, by suppressing the principal obligation and never mentioning the second, wink at a lukewarm populace with the suggestion that there is no more holy day. When the burden to attend Mass is removed, why should I further take on the "burden" to rest?
The 1983 Code does not offer the option of merely abrogating Mass attendance as the US bishops did; rather one suppresses the holy day entirely (as Honolulu did) or transfers it to Sunday (as in Ascension).
In short, these days are technically still holy days of obligation "in name only" with any mention of obligation being lifted when, by "calendrical accident", these days happen to impose "too great a burden on Modern Man of ambiguous and fluctuating gender".
It's a missed opportunity for a traditional priest to fail to point out the ridiculous madness of this situation—although some do—and instead inadvertently create greater confusion in the faithful.