

I can see it. They got caught in your use of from, which isn’t even incorrect. Via would have been a better word, but from works here just as well.
They’re reading it as you’re talking about pirating content that is owned by (from) your ISP, not what you meant, which is talking about pirating content from behind or via or even using your ISP. I guess through would have worked, too.
But the difference between me and them is, while I realise another word would have worked better, I understood exactly what you meant and didn’t think it was an issue. Though I admit I thought the first thing… at first. Hey, it’s early.
I think it depends on the ISP. There are a few small ones that do not GAF what you do. I’ve been told “we do not care what you download, we only care that you can.” There are a few big ones that are too big to care what people do on their network.
That said, you should always take precautions. A VPN is a good place to start.