I think you're right that a lot of par for the course friction between groups is being cherry-picked and made to look like a broad trend, when it isn't nearly so broad if it is anything.

There's a lot of cherry picking, and a lot of making up out of whole cloth.

An example of the latter: http://therealtruthproject.blogspot.com/2014/07/myths-about-saul-alinsky-and-obama.html with an addendum: http://therealtruthproject.blogspot.com/2014/08/what-did-saul-alinsky-really-say.html

Note that the mythical "8 levels" were so well established, in a way, that Yahoo is even now, spitting it out matter of factly, 3 months after I wrote my piece. I just tried it (entering: What are the 8 levels of control as outlined by Saul Alinsky?) to answers.yahoo.com

And yet, I warrant very few people have any idea that it's going around, unless they spend quite a bit of time on right wing web sites -- and read the comments, because the site's main author(s) -- at least on the more important blogs, won't be caught telling such flat-out lies.