Whereas the particular Jewish experience of subjugation and liberation was once the central expression of the seder, the persecution of others and their need for liberation has influenced the great majority of the changes to both the haggadah and the seder experience for American Jews.
In discussing this phenomenon with people planning seders over the last several years, they’ve often shared their concern that their non-Jewish guests or family members might feel excluded, if not offended, should their seders focus too much upon the historical Jewish experiences of subjugation and redemption or the threats facing Jews today. Some have shared that they omit entire passages in the traditional haggadah that reference the Jewish experience of persecution and liberation beyond that of the exodus from Egypt.
Ironically, I’ve found over the years that non-Jews attending seders come with the expectation, and often the hope, of experiencing a particularly Jewish occasion. When we opt to universalize the theme to the exclusion of the unique historical Jewish experience, we may be responding to our own discomfort with a particularized focus on our history of persecution or our desire to concern ourselves with the welfare of Jews living with less freedom than we might enjoy today.
I reject the notion that fighting for universal "persecution of others and their need for liberation" is separate from being "particularly Jewish". We are commanded: "Justice, justice you shall pursue!" (Deuteronomy 16:20).
This does not specify uniquely Jewish justice, nor does it imply we may rest when all Jews are free. The obligation to fight for the freedom of all people is in the core of Jewish thought, right at the intersection of "You shall remember that you were a slave in Egypt" (Deuteronomy 16:23) and "That which is hateful to you, do not do to your fellow".
Switching to a different Hillel, when I worked at Hillel we talked about being "universally human and distinctively Jewish", the idea being that there is a Jewish way to be a good citizen of the broader world. From that perspective I understand this essay; giving up the Jewish "flavor" (no, matzah doesn't count) devalues the seder as much as would ignoring the suffering of others.
"Let all who are hungry come and eat!", says the Haggadah, whichever version you may use. This is not diminished by the addition of universal themes to the seder; it is enhanced.