The first commandment concerns itself with what a person worships. Worship is the devoted service one gives to what one regards above all, and what one regards above all is that person's God. The first commandment says what we are to worship, the Creator God. Nothing else is to be given that kind of devotion.
As this verse shows, one can give devoted service to created things as well as the Creator. The people Paul is speaking of turned their attention from the Creator and to the created. It is possible to worship the wrong thing. In Colossians 3:5 Paul writes that covetousness is idolatry too, clearly meaning that our devotion can be given to things other than the true God.
There is a common argument in the world that "all religions are good," that is, none of them teach you bad things. But, as these verses prove, that simply is not true.
Paul argues that God gave these people up—literally, that God abandoned them to uncleanness. Therefore, any religion other than the one true one is a curse! It is a kind of punishment. These people that Paul describes exchanged the truth for the lie. How can that be good?
Here, the lie is that someone or something other than the true God can be properly worshipped and be effective for the person's salvation. Worshipping things other than the Creator turns the thrust and the direction of our lives off the true path of God's purpose. Though those objects that individuals give all of their time, attention, and devotion to may be otherwise harmless in themselves, it is sin to give them that devotion because it is "missing the mark," which is sin.