“All things are lawful,” but not all things are helpful. “All things are lawful,” but not all things build up.
1 Corinthians 10:23

"All things are lawful" in this verse is not a blanket statement for all behaviors in all circumstances. Paul was only addressing the specific circumstances of eating meat sacrificed to idols when you are not worshiping the idols. "All things are lawful" is more properly understood to mean "All otherwise clean meat is lawful even if it was sacrificed to idols". Even so, it is often good to abstain from many things that are morally acceptable but that might cause other problems, such as by the appearance of sin, which might lead a weaker brother to think the apparent action isn't sinful at all.