I think it has to do with the fact that they aren't buying the sites because they are Jeep enthusiasts. They are buying them with one purpose and one purpose only, making money off ads.
While there is nothing technically wrong with making money from ads, you're going to get a much better site in my opinion when it's run by someone who is actually passionate about it. For instance, I'm obsessed with Jeep Wranglers, as were the guys who started Jeep Forum and Wrangler Forum back in the day.
Vertical Scope doesn't care about Wranglers. They are a large company who cares only about the sites as a means of making money.
Because of that, after they took over, I watched things slowly go downhill. Trolls left and right, lack of moderation (and the moderators they do have seemed to be power hungry assholes), etc.
I could go on about it forever. Hell, I could probably write an article about it.
Either way, I started this forum (and the YJ and TJ forum) because I was disappointed how the other forums started going downhill, so I wanted to bring them back to life.