No offense to you personally, but this is a case where it's about grey hair more than ability.
There was certainly a time when Sourceforge was the wham-bam-snickety-snack boom-blam bomb. It was when Slashdot was the Hacker News, when "LAMP" was a new term, when 10Gbps across the U.S. (vs. your living room) was a Big Deal.
> If we'll look down in history, I think there are very few villains that have acted as heroes when starting out.
This is called playing "I told you so." In reality every organization begins with high ideals then adjusts to reality. The elegance of this transition defines how villainous they've become. Consider McDonalds and Whole Foods. Both seemed delightful at the beginning. We see how McDs is now cancerous (or at least diabetesacious) and Whole Foods is anti-union, but surviving anyway, a "mundane evil."
You can't predict which company will become evil or not.
But the underlying point is similar to "you are the product". People chose Sourceforge because it offered free hosting. It was for a long time the "default" choice, back in the early 2000s. They had banner ads, usually from other Linux companies, and that seemed to pay for it. It was easier to use than FTP sites.
The question always remains: who is going to pay for it? If a company is sinking, then they have only two options, to close it down or to engage in ever-shadier chasing of monetisation options. Can you imagine the outrage if they'd put up a paywall? It's basically the same politics as has made "free to play (with gouging IAPs)" the default mode of paying for mobile apps.
I do hate the "free to play (with gouging IAPs)" model and I actually prefer ads with an option to go ad-free. However even with this business model there are heroes. See for example Path of Exile, a free game in which the in-app purchases do not have an impact on your ability to win: https://www.pathofexile.com/
I do agree with you, the chosen business model makes the difference. I do believe that ads aren't inherently evil, it's just the status quo that is. Yes, today ad-supported means that we are the product, but this product has a free will, a fact that some companies are forgetting. At the very least there are some signs of change. Google for example is at least trying to play it both ways - you can be a paying customer of Google Apps and they'll introduce subscriptions to YouTube for going ads free (with the ability to cache content for offline viewing on mobile devices being the incentive needed for regular folks).
If Github ever pivots to selling t-shirts, run.
Ultimately someone needs to pay some bills though, a few transactions later and this seems remarkably far from their start. It's embarrassing and shocking.
The logical implication in that line flows in the other direction. It's not that every villain started out a hero, but that every hero (that survives long enough) ends up a villain. Of course, it's untestable as there's no limit on "long enough", but then again, it's just a line from a movie...
I remember a time when it was a fantastic resource, that it was one of the primary places to get FOSS - my earliest bookmarked link is for AFPL Ghostscript from 2004. IIRC I started using it around 1999 when I first installed Linux. There was Freshmeat too but that IME had far fewer of the major projects. Searching SourceForge was the best way to find projects for a particular need at the time.
The last FOSS project I downloaded there that isn't available elsewhere was last month.
If we'll look down in history, I think there are very few villains that have acted as heroes when starting out. The signs that such companies are assholes are in general there, from the start. As an example, I don't remember a time in which Sourceforge was the hero, as much as I try. Since as long as I remember Sourceforge, it was always the "necessary evil", the nuisance you have to deal with because bandwidth was (and still is) very expensive.