You guys can talk anti-AMA all you want, but the AMA provides insurance to EVERY offroad event that I ride (and it's a lot of them), as well as providing support for many national race series. Without them, I wouldn't be able to ride/race nearly to the extent that I do (and for a very small annual fee).
I believe that they are over-doing this E15 thing because they over-committed to stopping it. I don't like E15 either, but I'm also not super upset about the whole situation, and I think it is a bad use of resources.
I strongly disagree with mandatory helmet use. I don't want them spending a ton on money on that cause (in lieu of other causes, like offroad access), but I have trouble getting upset about it. If the public can tell us (as motorcyclists) what gear we need to wear to stay safe, why can't they also tell us what and where we can ride to stay safe? "2-strokes, fast singletrack, and desert racing are too dangerous..."
Finally, I will note that quite a few of the current issues on the AMA's website relate to off-road and OHV vehicles use, so claims that they don't care about OHV might not be well founded:
http://www.americanmotorcyclist.com/Rights/IssuesLegislationOld.aspx