It is not more designed and/or offered for this purpose than any other communication tool. At least I didn't see an evidence. The fact that it could be used is not sufficient. The goal of the whole exercise was probably more to set an example and to intimidate people a bit.
EDIT: That is probably why they called in the RIAA, which is quite peculiar. The RIAA is no copyright collective, is it?
I don't understand the RIAA bit.
That's not per se illegal. First there are countries where it is not illegal to download copyright protected content for personal use. Second even in countries where this was illegal (but where it is by no means clear what the difference between "download in the browser" and "download in another tool" should be) Youtube contains content which is CC-BY licensed (see e.g. https://www.youtube.com/user/RochusKeller) which can be legally downloaded and used.
> I don't understand the RIAA bit.
RIAA is no copyright collective (see https://en.wikipedia.org/wiki/List_of_copyright_collection_s...), but just an industry organization. In order to be able to represent the rights of the IP owners in court or in actions like the present one, the organization needs appropriate powers of attorney. This must also be provided for in the statutes. This is not the same as lobbying. If I was a representative of the other party, the first thing I would doubt is that.
Any video you watch requires you to download it, the only difference from a browser is how it stores the file. And section 1201 does not outlaw tools used for circumventing copyright, it outlaws tools used to circumvent copyright protection.
You can't simultaneously offer a video for people to watch and still "not allow downloads". What you actually mean is that they do not explicitly offer a downloading feature. That's true, but that's what the tool is for and it's not in itself illegal.