Denominationalism started with the Protestants, not the Catholic Church. We are not a denomination.
"The term "denomination" in general refers to anything distinguished by a name. In religious contexts the designation has traditionally applied both to broad movements within Protestantism, such as Baptists and Methodists, and also to the numerous independent branches of such movements that have developed over the years primarily because of geographical expansion and theological controversy.
Denominationalism is a comparatively recent phenomenon. The theological distinction between the church visible and invisible, made by Wycliffe and Hus and elaborated by the Protestant Reformers, underlies the practice and defense of denominationalism that emerged among seventeenth century English Puritans, who agreed on most things but not on the crucial issue of how the church should be organized. The eighteenth century revivals associated with Wesley and Whitefield greatly encouraged the practice, especially in America, where it became dominant.
After reading your link regarding denominations, it really points out how far afield from the original Catholic Church the Christian religion has come. As Martin Luther said on his deathbed (I'm paraphrasing here) now any Milkmaid can start a new religion. Even Martin Luther had a momentary vision of what was to become. In our day and age, I see many parallels with the Hellenistic Age, when sects and cults multiplied greatly. The Hellenistic Age was one of great uncertainty, with many wars and societal instability. Just like today, when we live in an age of great uncertainty, and new denominations, sects, and cults are springing up with great regularity. What goes around comes around.
"Denominationalism started with the Protestants, not the Catholic Church. We are not a denomination."
The word "church" is a translation of the Greek "ekklesia," which means "those who are called out." All Christians, whether they be catholic or non-catholic, are called out of the world by Jesus, thus we are all part of that body of people which the bible calls the "ekklesia." Any one group which is a subset of that body and which denominates itself by some name (e.g., catholic) is a denomination.
I'm as much a part of Jesus' church as you are. In as much as I am in communion with Jesus, I am in communion with His church. It's His Spirit in us which unifies us, not some outward allegience to a denominational subset of the church.