There are so many bible verses that declare Jesus to be the only true Lord and that all other religions worship in vain that are too numerous to count. Here are three for example:
6 Jesus said to him, “I am the way, and the truth, and the life. No one comes to the Father except through me. 7 If you had known me, you would have known my Father also. From now on you do know him and have seen him.” (John 14:6-7, ESV)
11 This Jesus is the stone that was rejected by you, the builders, which has become the cornerstone. 12 And there is salvation in no one else, for there is no other name under heaven given among men by which we must be saved.” (ACTS 4:11-12, ESV)
5 I am the vine; you are the branches. Whoever abides in me and I in him, he it is that bears much fruit, for apart from me you can do nothing. 6 If anyone does not abide in me he is thrown away like a branch and withers; and the branches are gathered, thrown into the fire, and burned. (John 15:4-5, ESV)
Now how we are to view those without faith in Christ is how we are to view lost sinners who pretend to worship God. Those without Christ who pretend to worship God are out of necessity idolaters for they worship images in their own mind that blaspheme the grace of God in Christ. This is not to say there is not some ‘truth’ in all religion, it is only to say that the glory of the gospel is perverted so badly that the end result is the human religion that they use to replace it. God wrath is against all these false religions.
18 For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who by their unrighteousness suppress the truth. 19 For what can be known about God is plain to them, because God has shown it to them. 20 For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse. 21 For although they knew God, they did not honor him as God or give thanks to him, but they became futile in their thinking, and their foolish hearts were darkened. 22 Claiming to be wise, they became fools, 23 and exchanged the glory of the immortal God for images resembling mortal man and birds and animals and creeping things. (Romans 1:18-23, ESV)
At the time of Christ idols were physical and in some religions they still have them, but religions that hold ideals or beliefs about being saved by their good works, rather then faith in Christ alone, are no less idolatrous than mere idols made of stone. The idols are still based out of their foolish hearts resembling mortal man and not the only Son of God who died as an atoning sacrifice for our sins. Current Judaism of course suffers under the same curse for it still rejects its only hope, Jehovah in Jesus, the only Christ of God, the only true God.