Imagine we're talking about CDs vs. MP3s and pat makes music. I'm not advocating not paying Pat. I'm advocating paying pat for the MP3s and eliminating the waste of the CD.
That Pat is encouraging people to still buy the CDs means either Slackware users haven't moved on or Pat hasn't.
You can donate to the project directly if you wish by going to http://store.slackware.com/ and clicking on the donate button (top of left column).
Now, to address your point about encouraging buying the DVD or not, I think you should view that from the marketing point of view. He offers software. There are no licenses involved, and you can download the DVD from many high quality mirrors. Still, he needs money to continue the project. Apart from praising the product, how does he market it and get people to pay for it? I think it's much better and professional to offer a pressed DVD in a jewel case, in exchange for money, than asking for donations or something similar. Even if it's less green.
Disclaimer: after years using Slackware, I got a subscription to the DVD when I got my first full-time job. I also think it's nice to receive the DVD from time to time, and I've used the DVD as a rescue and installation disk occasionally. You don't know when it can be handy to have it.
