As we've stated several times in the past, we do quite a bit! I can't go into details about things due to various sensitive topics (or things that would be bordering on "legal advice" if I were to state it on behalf of VRChat) but here's what I can tell you:
** Most (if not all) avatars added to that site cited in the video are added via people running a client modification that silently steals and uploads avatars to their servers.** Stealing then gives those people tokens, which they can use to download rips. In short, if you know people that are breaking our Terms of Service via running client modifications, they could be running that client modification. We fight as best we can against that, but as you can imagine it isn't easy.
Ripping in general is impossible to stop as many people have pointed out. Even the biggest companies on the planet don't have a solution. If we somehow made a tech that fixed it, we'd probably turn around and sell it to other companies for trillions of dollars as we'd have just solved a very tough security problem: "How do you let someone use an asset in a program on their computer without letting them have it on their computer?" Spoilers: the solution is making VRChat a Google Stadia / GeForce Now exclusive. Nobody wants that. 😛
We do as much as we can to make it difficult as often as we can without it affecting our continued development of VRChat. Pouring time and money into a "perfect" solution, however, is unwise. It would be a very fast way for us to "spin tires" and run out of resources and ultimately accomplish nothing.
Finally, regarding that site in particular-- and reiterating that this is not legal advice and should not be construed as such-- if your rights have been violated and content that you own appears on that site, you have options available to you that would permit you to request that they take down the content. Of course, it is just a request. They can ignore it-- and from personal experience, can tell you that they do ignore it. I still try anyways. 
I hope that clears things up. We can't talk much about it because it is a security topic and any information we share makes our security a tiny bit weaker. We're on VRChat all the time and see these things as often as you do. I've had my own avatar (which I own 100%) taken hundreds of times. It sucks, but with the freedom you have on VRChat to upload anything you want, you also have downsides. This is one of those downsides.