Because of several reasons, all of which are found on google and elsewhere.

I'm sure your penis is 10% larger now. You really needed it.

So I'm reading this article:

http://privacy-pc.com/articles/hackers-guide-to-stay-out-of-jail-7-vpns-vs-tor.html

In terms of technologies that you can use to help ensure that you maintain good OPSEC, on the subject of VPN vs. TOR, a lot of people seem to have thought that VPNs provide anonymity; that’s not the case. VPNs provide privacy, TOR provides anonymity, so the difference is: privacy protects your data, anonymity protects you. Therefore if you are using a VPN service, you have to make sure that you’ve gone through TOR first, otherwise that VPN is simply a link from the end point to yourself. So, TOR to VPN – ok; VPN to TOR – go to jail.

Why is VPN to TOR a problem? If you are doing it, then the endpoint sees IP of TOR's exit node, so you get all the benefits of TOR but this way your ISP can't see that you are using TOR. So it seems like best setup to me. Why is TOR to VPN better?