Is drop shipping books allowed on Shopify?

[Henny1]

I started this account 6 months ago and built up a store of 400 books that I source from Amazon.

Not much sales so far. About 10 sales in the last 4 months. The Shopify subscription costs me more than the profit on the books. 

Yesterday a new sale. 

Now suddenly "Shopify Risk Operations Support" sends me an email that says they need to verify I am an authorized reseller. 

Huh? ?? 

And oh, they are freezing all payments until they have completed their review. 

As far as I know drop shipping books is not only legal, but also standard practice on 1000s of websites. Because all parties benefit. 

So my question: Is drop shipping books allowed on Shopify? If not, why not?

[ShipAntdotcom]

Lots of restrictions for the books, for example, IP, politics, porn, religion etc.

[Henny1]

Nobody can explain to me that if I dropship books from Amazon to my customers in the Netherlands, there is a law that prohibits this. 

Dropshipping books is an ages old practice, even Amazon started out doing this in 1995. 

Political, religion, porn, etc, I can understand rules specifically directed against that. But that is not what this is about.