Why do you want to talk about these heresies?

"The Church isn't one group or another. It's everybody who has faith in Jesus. There's no perfect Church because there's no perfect people. Even if the Church used to all have the same teachings, people are sinners and they went into error and the Reformation changed that. There's errors in the other churches, too, but that doesn't mean they're all wrong."

Just off the top of my head, these notions deny the very nature of Divine Revelation as recorded in the Sacred Scriptures.

Of all the progeny of Adam, Sem alone together with his descendants preserved true religion ---> when the Nephilim contaminated mankind, Noe alone was found to be "perfect in his generations" and he and his family were saved from the Deluge ---> of the postdiluvian peoples scattered about after the Tower of Babel, God chooses Abraham ---> of his children, Isaac is chosen as the son of promise ---> then the same happens with Jacob ---> Moses is later chosen as the Legislator for the Jєωs ---> In Exodus, Leviticus and Deuteronomy various precepts and ceremonial laws are promulgated to make sure the Jєωs observe all the types that prefigure the coming Redeemer ---> the Prophets are sent by God to rebuke the idolatrous Jєωs before and after the Babylonian Captivity ---> the promised Daughter of Adam who would crush the head of the serpent is born, the Immaculate Conception, fore-chosen to be the Virgin Mother of God ---> Our Lord chooses twelve Apostles (Judas reprobates himself but St. Matthias is chosen in his stead, restoring the twelve; and later St. Paul is chosen by Our Lord as the "Vessel of Election"): the Apostolic College under the supremacy of St. Peter are the foundation of the one Church established by Christ, which is to both fulfill and efface the ancient ѕуηαgσgυє ---> throughout the Acts of the Apostles, the ministries of the Apostles is shown to be the continuation of the One, Holy, Catholic and Apostolic Church ---> in the Apocalypse of St. John, the history and future of the same Church is revealed, and the Holy Mother Church emerges triumphant together with Our Lord.

So, from the beginning God intended: 1) for His Divine Revelation to be made in a public and visible manner, as seen ultimately in the ѕуηαgσgυє and after Our Lord fulfilled the Scriptures in the Church; 2) to have a specific number of elect who would have been sifted continuously from Adam's progeny to the remnant of Jєωs who were awaiting the advent of Our Lord, and then to the Church who would preach the Gospel to the Gentiles; 3) only one economy of salvation was to exist, not a concurrent or simultaneous plurality of economies, meaning only one Church is to be the one established by Christ and to have been assured perpetuity and infallible authority.

It is ridiculous to assert that God intended for His Divine Revelation to be arbitrated by the whim and fancy of fallible and corruptible individuals who would contradict one another and ultimately undermine the very nature of Divine Revelation: only one Church was to be especially forechosen to be guided by the Holy Ghost to preserve the deposit of the faith. This Church is the Catholic Church.

"The Church isn't one group or another. It's everybody who has faith in Jesus.

This is not correct.  The Church is One, Holy, Catholic, and Apostolic.  Only the Holy Roman Catholic Church completely fulfills this definition.  While I accept that there is a possibility that there could be people who have true faith in Jesus and who may achieve salvation (i.e., Baptism of Desire according to the mind of the Church), though this group is exceedingly small, they are not actually incorporated into the Church unless, through miraculous means, they find themselves members of the Church Suffering.

There's no perfect Church because there's no perfect people.

A non-perfect Church would not be Holy.  Of course there is a perfect Church.  The problem we face today is that an apostate sect has co-opted the name of that perfect Church and stolen its property.

Even if the Church used to all have the same teachings, people are sinners and they went into error and the Reformation changed that.

The first part is a given.  The Church continues to have the same teachings as it has always had.  People are indeed sinners and have gone into error.  The so-called Reformation, really the Revolution, only changed the errors and multiplied them each sect splitting over increasingly fractured errors.

There's errors in the other churches, too, but that doesn't mean they're all wrong.

This is just plain silly-talk.  Error is, by its very definition, wrong.  Every sect, be it Protestant, Jєωιѕн, Islamic, Hindu, Wiccan, Buddhist, Sikh, Orthodox, Conciliar catholic, etc., etc., etc., is founded upon error and is, therefore, wrong in at least one critical doctrine of the faith.

It would be impossible to truly have a discussion with anyone who makes the final statement because that individual simply will not accept the self-evident truth that error is, by its nature, wrong.

 :thinking:
Many of us have no choice but to be surrounded by heretics and pagans.  If one is in the world, there is no avoiding them entirely.  They are one's family, coworkers, neighbours.  
In a nutshell, God founded only ONE Church, not many, and simply believing in Jesus doesn't get a person into Heaven.  The devil believes in Jesus!  So he's going to Heaven?  
StephenFrancis, if the people of whom you speak are willing to honestly investigate the claims of the Catholic Church, they will listen to you and read materials you give them.  IME, such persons are rare.  Most say, "Don't confuse me with the Truth.  I've made up my mind.". With these, it is best to keep your silence.