By your logic nobody can ever disapprove of anything and be taken seriously because you can simply claim that anyone not on the boards is by default approving of the change. It doesn't work that way.
The removal of solo queue didn't bring me to the boards. Getting back into the game did. I started to come here during the champ select/loading time, like I imagine many other people. People don't come here because they want to gripe, they come here because they are into League.
What causes people to post, however, is a different story. The reason you see more "negative" posts is because most people don't have much to say about League related mechanics, strategy, and etc. They listen to what others say and try to learn, laugh at a humorous post, etc. But when something comes along and screws their game up, they have something to say about it, so they do.
The silent majority are the same people coming in and quietly upvoting the anti-DQ posts which resonates with their experience, the people trying to make sense of these sweeping changes to what has otherwise been a relatively stable gaming for the last 5 years, and the people slowly trickling out of the player base towards a more stable, less toxic gaming experience.
DQ is inherently flawed. By its nature it removes both the stability and the competitive aspect of ranked play. It narrows League from an environment that supports a broad, diverse player base to a narrow one. Play with your friends, be someone who is willing to accommodate a group of other people's friends, or don't play.