Why do some Christians say that the Catholics worship Mary and the saints when they ask them for intercession?

I know that by praying to Mary and the saints, a person is THOUGHT to be breaking the commandment about not bowing to anyone other than God.

But if a person is praying to Mary and the saints, aren't they just asking them for intercession? Where is the worship in that? It's not much different to asking others for prayer requests.

And some people hold Mary in high importance but they're not necessarily equating Mary to God.

I know that nowhere in the Bible are we told to pray to Mary, but nowhere are we explicitly prohibited from doing so either. Yes King Saul called up Samuel through a medium but Catholics don't use mediums.

However, one interesting thing is that the saints are said to be alive in spirit even as they're physically dead.

However, the way I see it is that they're still dead. We don't know if they're in heaven.