> the disproportional anger from car drivers both on the road,
> and elsewhere (online, dinner conversations, etc) over the
> practise of "lane splitting" by bikers (motorcyclists) even
> in states where such practise is entirely legal.
Perhaps it's because of the disproportional propensity for many motorcyclists to split lanes even when it's not safe to do so. As an example, in California there are two references:
1) The CHP says it's legal to lane share if it's "safe and prudent"
http://www.chp.ca.gov/html/answers.html#03
2) DMV says in their motorcycle handbook that "Lane sharing is *not* safe" (their emphasis)
http://dmv.ca.gov/pubs/dl655/dl665mcycle.pdf
It is "entirely legal" (OP redundancy) to lane share; it is also "entirely illegal" to act in an unsafe manner.
Which do you think is the more common case?
/jordan