I think that for people with an svn background there are three different issues that all hit at once:

* distributed rather than centralised version control brings a new set of concepts to understand

* git is flexible enough to support many different workflows. This means you have to actually choose one, and choice is difficult especially when you're just trying to get to grips with a new tool. svn has much more of a "one standard way to do it" approach

* git's UI is in places confusing, inconsistent and occasionally just randomly and unnecessarily different from most other version control systems

The first two are 'essential complexity'; the third is more 'accidental complexity'. In any case I feel it's having to deal with all three sources of confusion that makes the svn->git transition tricky for many people.