The way that this issue is framed, even by people who should know better, is profoundly misleading. These are not "anti-downloading measures". Viewing data from a remote machine without first downloading it would be a very neat trick.

It is therefore nonsensical to ask "Is it okay to download this video without the creator's permission?" in this context. The creator has given you this permission. The question we should ask is "Is it okay for the creator (or some intermediary) to take control of my computer in order to delete some data after I've acquired it perfectly legally?"