I agree that the owners of Slashdot are free to take it in another direction if they want. Presumably what they desire is more money, and they believe the redesign is a way to increase ad revenue. So far so good.
In this case, however, I believe their strategy is not a good one. If you alienate the commenters, then they will leave, and all that will be left is a stream of story digests with links to other sites. The bulk of their readership (all those people who come to Slashdot but don't comment on stories) will go to other sites (there are plenty that do a better job of finding and organizing links to interesting stories). The only differentiator that Slashdot has is its vibrant and intellectual community, which leads to interesting discussions, which in turn justifies actually visiting the site. Once the commenters leave, your revenue stream (ad impressions) will go away.
The problem is, most slashdot contributors I don't think click on the ads. So frankly as a community, you're not that valuable.
There is some truth to this. Slashdot users are probably less likely to click on ads than the average person. We are probably more aware of advertising tactics, and may thus avoid being influenced (to the extent one can). Slashdot users are probably more likely than most people to use ad-blockers. On the other hand, Slashdot users occupy a huge number of key decision-making posts in all the major tech companies. Even 'lowly' employees can have a huge impact on what their employer spends money on. I would also note that an ad is not necessarily a failure if no one clicks on it. One of the main purposes of advertising is awareness and branding. If you see ads for a given company on Slashdot, you will subconsciously become aware of them, making it more likely that you will consider them when making your next purchase. No clicking required.
I fully admit that it is difficult to quantify the 'value added' of advertising to the unique Slashdot community. I would hope that Dice has made this case to their ad partners; I guess it wasn't enough?
And what's wrong with that? They have ongoing costs in terms of servers, IT support, and the moderators. Word is for the most part the Slashdot revenue stream has been shrinking for Dice, which means they'd be bleeding money.
Actually it's not clear to me that's the case. The things I've read indicate that revenue coming from Slashdot is decreasing with time. But this isn't the same thing as saying that Slashdot doesn't generate enough revenue to pay for operating Slashdot. From what I can gather, Slashdot is a net money-maker... it's just not making enough money, and the owners want to make more. (If someone has better info, please share!)