Ted Kennedy isn't himself the sort of figure one would expect to arouse more than normal political feelings -- a sometimes boorish and boozy character, but a party loyalist able to bring a fair amount of rhetorical power to pushing his party's line and able to bring a self effacing charm into play (when he tried) which softened his partisan edges. Not the sort of person I'd tend to admire, but also not someone I'd feel called upon to rail against.
I think the issue is that the combination of the Kennedy name and the Democratic party-line positions holds a certain place in American Catholic history which causes strong reactions among various Catholics depending on how they reacted to that period in Catholic history in this country. JFK was elected at a point when it seemed Catholics had finally "arrived" in the US. They'd made it out of the ethnic ghettos, through college, and into mainstream American society. And while public schools were heavily Protestant, and Catholic "smells and bells" still looked very strange to WASP eyes, Catholicism had become a large and mainstream religion in the US complete with famous converts and Fulton Sheen as a major TV personality.
With urban Catholics forming one of the mainstays of the Democratic party, idealistic young Catholics of the 60s generation found themselves at the forefront of supporting the civil rights movement, opposing the Vietnam War, and supporting the Great Society programs. With the "Spirit of Vatican II" reigning supreme in from the mid sixties to the mid seventies, the future seemed to belong to the progressives within the Church as well.
And so when the cultural results of the sexual revolution and increased secularization in the culture became absorbed into the progressive movement, many progressive Catholics seem to have decided that increasing numbers of moral issues (first contraception and abortion, then gay marriage, cloning, embryonic stem cell research and euthanasia) were expendable in order to further the programs they believed would fight poverty, support unions, avoid war, and provide better health care and education to the needy. Meanwhile, many other rank and file Catholics sought a political home in the GOP, but arguably the GOP remains to this day a heavily Protestant party, though Catholics and Jews have become prominent among its intellectuals and policy makers. It is not Catholic in the way the Democratic Party (in the northern states) was in the first half two thirds of the 20th century.
This, I think, is where the division and the strong feelings involved in it come from. On the one hand, we have a group of Catholics who have come to identify virtue almost entirely with casting votes on specific "social justice" issues -- regardless of personal morality or one's stance on other issues of arguably greater moral gravity. Maureen Fiedler stands very much in that tradition when she write a post for National Catholic Reporter about Ted Kennedy entitled, "He made me proud to be a Catholic," and saying:
Ted Kennedy, like his brothers, was a champion of civil rights, women’s rights, and the welfare of the “least of these.” He strongly and eloquently opposed the war in Iraq. Because his life (and the lives of others in his family) embraced the great Catholic social justice tradition, they have made me proud to be a Catholic.
The other school of Catholic thought is more diffuse, in that it contains both those who agree fully with the above "social justice" issues, but holds "values issues" such as abortion, same sex marriage and euthanasia to be at least as if nor more important -- as well as continuing to hold to the importance of personal moral decisions -- and also those Catholic who question whether "social justice" and the progressive political policy solutions are synonymous. Surveying the post-war era of the 20th century, I at least do not think it in appropriate to question whether continuously building up the reliance of the individual on the state and its programs (to the exclusion of all other more subsidiary relationships) is in fact in keeping with human dignity and thriving.
Perhaps as a symptom of this, I find it hard to imagine having such a passionate regard for a Catholic politician as Fiedler describes in her piece. There are some Catholic politicians I'm moderately impressed by (Sen. Brownback and Gov. Jindal spring to mind) and some Catholic intellectuals who dealt with political topics that I am fond of (Buckley, Fr. Neuhaus, Ramesh Ponuru, Ross Douthat) but I can't envision myself saying of any of these "he made me proud to be Catholic." Indeed, the only people I can imagine writing that about are professed religious or clergy: Mother Teresa, John Paul II, Benedict XVI
This is not to say that only those under religious vows are living out their vocations as Catholics, but that being mindful of the fracturing of Catholic group identity, I would in many ways see primarily those of in the religious life as devoting themselves so totally and clearly to the work of the Church that I'd see it as appropriate to say, "he made me proud to be Catholic," about someone. The phrase suggests to me not merely a commonality (I liked him, and he happened to share the characteristic of being Catholic) but rather a sense that the person being described embodies how a Catholic ought to live out his life. And this, of course, makes it something which people are going to argue about (and feel strongly about) when someone they have strong reasons to object to from a Catholic point of view is held up as someone who "made me proud to be a Catholic."