Without Opera, Firefox wouldn't be what it is today. Without Firefox, we would have all still be stuck with the crappy old IE6. Without Firefox, we wouldn't have Chrome. Without all these alternatives to IE, the world would be much worse off, held hostage by Microsoft's blatant barstardisation of standards, and its many terrible practices of wiping out competition.
Although Opera only owns a small percentage of the browser market today, the web and internet would not be what it is today, had Opera not existed. I guess we could probably say the same for the mobile Web.
Your argument is something along the lines of telling IBM to shut their mouths because they aren't anything great, and have a tiny share of the market compared to Microsoft / Intel / Dell / etc.
Opera have earned their right to throw their arguments into the ring. They might be small, but they are well respected all over the world by IT professionals, especially those with more in-depth knowledge of the industry.