Obedience to the churches teachings(catechism) is key to being catholic, why else would we affirm the church in the creed? Why else would we have a catechism at all, if not as a guideline? 
How would you approach people who wilfully disregard or disbelief, and still affirm themselves as catholic? People like me get confused because we are supposed to have the same faith, and same goal of becoming saints, through humility, penance and sacrifice emulating the beatitudes of our Lord.

I guess what I am asking is how would you define a catholic?

Oh, and what did you think of the didache by the way? I was personally surprised at how much remains intact and ingrained in the Church to this day.

About trumpism, perhaps it is not as black and white as you paint it. Perhaps they voted for him, not due to ideological affinity, but due to him being seen as the lesser evil, especially in light of Podesta's  attempts to subvert the Church from the inside.