You're not alone in that regard. Not by a long-shot. You write pretty well on details about your thoughts and you try to be respectable along the way. That I can fully understand, even the apologetic tone (which I myself tend to use whenever I bring up a more controversial or off-topic subject to a debate). There is nothing to be ashamed of expressing your own opinions or your ideas. No matter how hostile the forums may appear to be, you will always find support and friends here. Personally, I find myself agreeing with most of your opinions on the anime. It's not worthless as you think.
Oh I know that feeling of having my own opinions being rejected at large by the rest of the Internet. But I manage through by speaking softly and small at the beginning, and watching how others react to other posts. Overtime, I became more bolder with my opinions and took my stance, and you would be surprised how many would agree with or support you. There will always heavy and fierce disagreements, make no mistakes. But if you can't make a counter-argument, leave it be instead of trying continue onward in some manner (because they never end well).