Molok is the name used in the Bible for a Canaanite deity that the Israelites were forbidden to "suffer their seed to pass through the fire to". Details are scarce, but this is usually taken to refer to human sacrifice. It later became syncretized with reports of child sacrifice at Carthage, where the popular imagery associated with Molok (the idol with outstretched hands, the drums) is taken from.
Carthage and Canaan did share many cultural traits, and the Carthaginians also called themselves Canaanites. It's quite plausible that the Carthaginians would indeed worship Moloch and make sacrifices to that god, and that the mentions of child sacrifice in classical sources about Carthage are based on such.
I think it's still inaccurate to refer to Moloch as Carthaginian rather than Canaanite. The latter is obviously correct, though a bit vague. The former is contested and not as clear.
Wikipedia probably has a better answer, but basically the name Moloch is from the Bible. One of the ways genocide of the inhabitants of Canaan (the promised land) is justified is by describing Canaanites as immoral people who sacrifice their own children to idols. Moloch is supposed to be one of the idols, but the actual history of Moloch is very sparse. Probably was one of the main local gods way back in the day like Baal. Probably not even an "evil" god at all (like Baal) since the Bible is heavily biased against the competing local gods in the region.
So basically, a god of Canaanites we only know about from the people that wanted to wipe them out and wrote very influential texts.