how can all things be lawful?

12 All things are lawful unto me, but all things are not expedient: all things are lawful for me, but I will not be brought under the power of any.

What does this mean?

1 Cor 6:12 In the margin it explains that the word "lawful" could also mean "profitable"
although the following 6 verses deals with sins
If you see that by doing certain things which you have
a perfect right to do, you hinder the work of the truth, refrain from doing these things. Do nothing that will close the minds of others against the truth. There is a world to save, and we gain nothing by cutting loose from those we are trying to help. All things may be lawful, but all things are not expedient. {SW 70.3}
"We have no right to do anything that will obstruct the light which is shining from heaven; yet by a wrong course of action we may imperil the work, and close the door which God has opened for the entrance of the truth.

thanks