I do believe it appears that you may have been out of line with your parents. Not knowing everything, I can tell you this, there are few times when it is necessary to correct our parents verbally. I cannot convince my mother through harsh words or reason that it is a sin to shop on Sunday. I've tried showing her moralists, she doesn't understand why the Church needs moralists to explain things or why they have the authority that the do.
At some point you have to realize it isn't in the will, it is in the intellect. People can't understand what you are saying to them.
So, I just remind my mother that we don't shop on Sunday. She already knows why, and I leave it at that.
Every Catholic knows we avoid houses of scandal, and we would only visit for good reason, which would be trying to convince the dwellers to give up cohabitation and confess their sins. That is not shunning, it is the refusal to acknowledge a sinful situation and give approval. A father might meet up with his son separate from his sinful life at a public place, or make other accommodations for visiting his child, without reference to the live-in. It all depends on the situation.
As for telling people about why we dress modestly, our main reason is because of our love of God and neighbor. Not because we don't want to sin, obviously we don't want to sin, but if you tell someone we don't do it because it is a sin, you are implying that you might do it otherwise or would like to do it otherwise. Our primary motivation should be to love God perfectly, not hellfire. If you start rattling off to a non-Catholic about mortal and venial sin, you are taking a chance they have no idea what you are talking about. Edification of your neighbor is about teaching them how to love God, not telling them if you don't do xyz, you are going to Hell. At hose strong words are for unrepentant sinners who know better. Like traditional Catholics who turn away from God to a life of sin, or obstinate, relentless heretics who know and understand the teaching of the Church, like Luther, or Arius.
You have to take people where they are at, work with what you have, and tread carefully. In your case, you aren't making many converts and you causing strife unnecessarily. (Btw, I think I said unnecessarily, but auto correct changed it to incessantly)