How can you not? Four of the ten address nothing other than religion. No other gods than God, No graven images, no taking the Lord's name in vein, and keeping the Sabbath. Those are strictly relgiious, and they're the first four commandments given.
As a Christian myself, I cannot in good conscience lie and say the 10 Commandments don't endorse a religion, because the first four things only apply to Christians and Jews. There is nothing universal there that can be applied outside of the Judeo Christian sphere.
I don't think of Judism or Catholicism or Protestism when I see the 10 Commandments. I don't worship the 10 Commandments, I worship the God who wrote them. In an of themselves, the 10 Commandments are not a religion.