This is one of those ideas which conflicts with much of the pluralistic concepts of modern Western culture. And so also where the concept of "freedom" has become the practice of lawlessness. To be a holy people there are relationships and associations which are disallowed for the Christian, or at least to be avoided. So also with activities. And so also with respect to ideas. While historically there have been many examples, even in Jesus own day, where such ideas are carried into legalism, but today in this culture - that of Western society - the problem is not one of "legalism", but rather of licentiousness.
Today in the Christian community you'd generally be labeled a "legalist"
if you are were in fact Biblically centered in your behavior and relationships.
So don't let such labels concern you. But consider what relationships,
activities, and ideas you should "leave". What "unclean things" do you
need to stop touching on? Remember that you are not just carrying the vessels
of the Lord, you are the vessels of the Lord. God appreciates purity.