It's good to know what people mean by what they say. Unfortunately, miscommunication leads to many unnecessary disagreements and divisions. It is funny how people fervently use words whose meaning they clearly don't know.
Like legalism. There is a big difference between being strict and being legalistic. Legalism is adding to the commandments of the Lord, not simply asking people who claim to follow Him to do what He has already commanded them to do. Jesus didn't get after the Pharisees because they told people to follow the Law. Rather He got after them because they added commandments to God's commandments in order to make themselves look good, while they totally ignored the actual commandments of God and lived lives contrary to them.
Similarly, when the Apostle Paul contended for the freedom of the Gentiles from the Law, he was not doing anything new. Naaman was not compelled to follow the Law when he was healed by Elisha. Nineveh was not compelled to become Jewish at the preaching of Jonah. So why would God, who through His prophets had foretold the salvation of the Gentiles, put this burden on the new Gentiles?
This same Apostle Paul was the one who commanded that Christians abide by the moral law: "Owe no man anything, except to love one's neighbor as himself. For he who loves his neighbor has fulfilled the whole law" (Romans 13:8-10).
Jesus said the same thing and challenged the salvation of those who called Him, "Lord, Lord" and yet disregard His instruction (Luke 6:46; Matthew 7:15-23).
Does this mean that salvation is by works? Hardly. It means that Jesus came to "save His people from their sins" (Matthew 1:21) not just from Hell. In fact, Jesus taught that the way to avoid Hell was to take the most drastic of measures to keep from sinning (Matthew 5:27-30; 18:7-9). Paul said, "Let everyone who names the name of the Lord depart from iniquity" (2 Timothy 2:19).
The only way to do this is to live in grace: that is what Romans 6 is all about. Grace, or Spirit-filled living, does not allow us to sin to our hearts content and remain in Jesus' "good graces." Rather it empowers us to overcome our sinful tendencies and the temptations that bombard us every day. This is what Jesus meant by "If any man come after me, he must deny himself, take up his cross, and follow after me [i.e., walk in His steps]."
In short, Christianity is about living life on God's terms, being grateful for His passing over our iniquities, not about us getting over on God: "Be not deceived: God is not mocked; for whatever a man sows, that also shall he reap. He who sows to the flesh shall from the flesh reap corruption, but he who sows to the Spirit shall from the Spirit reap everlasting life" (Galatians 6:7-8). Jesus' beef with the cities He upbraided in Matthew 11:20ff was that they did not repent, not that they didn't believe He existed, not that they didn't believe in God, not that they didn't go to church.
So, when it comes to commands like sobriety (i.e., not getting drunk or high), modesty in clothing, fornication, honoring parents, etc., it is not legalism that drives those who ask people who claim to be Christians to adhere to the Biblical standard. It is Jesus Himself.
Now, are some people too strict about it? Maybe. It might be that they are strict because they have seen people ruined by ignoring God's commands. It might be that they heard about the commandment but don't understand it well enough to communicate it properly with the person they have taken to task.
But it might be that they are just right and we need to repent. Because walking with Jesus means that we have to change. And we have to change a lot of things that we like(d) doing. There is pleasure in sin for a season, but the end of it is death. Is it worth "piling up" the grace needed to save ours souls only to discover that in our love for sin has caused us to miss out on God's grace entirely?