Is the worship of God idol worship?
There's a Buddhist saying that goes "If you see the Buddha on the road, kill him.
There's a Buddhist story of a monk and his student, alone in a monastery in the snowy mountains. A giant, wooden statue of the Buddha stood in the hall. The pair were starting to freeze, so the monk told his student to toss the statue of the Buddha onto the fire, so that they could get warm.
The student, eyes wide in shock, asked "How you be so disrespectful to the Buddha?"
The monk responded, "That statue is not the Buddha.
Both the saying, and the story, so far as I'd guess, discourage different forms of idol worship.
In the story, the student is practicing a kind of idol worship of a statue. He is placing the statue on the level of the Buddha and telling himself the statue is the Buddha. This was undoubtedly a subconscious mentality. He wasn't thinking, "I want to worship a wooden statue." He was merely thinking, "This symbolizes the Buddha, so I want to show respect to the Buddha through it," but it's that thinking...that presuming of what the Buddha wants that is what makes the stronger form of idol worship.
Now, back to that saying: "If you see the Buddha on the road, kill him."
That's, presumably, because if you see the Buddha on the road...that's not the Buddha. I would say, too, that if you think you see the Buddha in your mind, it'd be best to keep in mind that's merely an impression in your mind, rather than the real Buddha.
Human beings love to invent gods for ourselves, and I think the ancient Buddhists knew that, and warned against it.
Now...what about God? How much do we really know of God? Who has seen the face of God? I would say we know little to nothing of God, and anyone who believes they know pretty much anything about God, whether through the reading of holy texts or any other means is engaging in idol worship...
...but I would argue that's not necessarily a bad thing.
Frank Lloyd Wright once said, "buildings too are children of Earth and Sun." He personified those buildings, because he cared about them, and oftentimes when we personify things that helps us to care about them further.
Albert Einstein, I believe, did something similar with the universe when he said he wanted to understand the mind of God.
I believe many of these more casual forms of personification can give the universe a magical feel. They can inspire. They can be quite lovely, and so long as we keep an open mind, these views may be harmless to benevolent.
It's the more serious mentalities that concern me...the perspectives in which a person has great confidence that their view of God is correct, regardless of how well-studied it is. I suspect its these people, these serious believers who are likely most wary of idol-worship, who tend to be the biggest idol-worshippers.
Many of them might be compared to the most enthusiastic worshippers of the golden calf, whereas many of the agnostics and free-spirits might be compared to the folks on the sidelines, gazing at the golden calf and merely admiring the artwork.