The formation of the KC had more to do with a consortium to be able to get life insurance. Catholics couldn't get life insurance for a time.
To understand why the church forbids freemasonry, the best source is a papal encyclical by Pope Leo XIII (IMO, one of the best and brightest of the last 200 years) called "Humanun Genus" published in 1884. There are other encyclicals by other popes that explain why, but Leo XIII always lays things out well. My HTML cheat sheet is at work, but you can find the encyclical at http://www.vatican.va/holy_father/leo_xiii/encyclicals/documents/hf_l-xiii_enc_18840420_humanum-genus_en.html
My prayers for you in your spiritual search.
Thanks for posting that link. I hadn’t read that before.