"You don't pass stationary bikes? Why ever not?"

Stationary in this context MEANS stopped in a lane that I am in, as at a red light....even IF they are at one edge of the lane.

"Why is it dangerous and who to ?"

Because motor vehicles do not expect traffic in non-existent lanes! They begin to edge over, in preparation for changing lanes.... they stick their arms out of the window... and a cyclist who cuts it too close can scratch or damage cars.....and various other possible problems.

Strange law? See above...the law establishes rules which, if everyone follows them, will provide the best OVERALL safety for all...even IF a few cyclists feel 'slowed'.
These questions indicate to me that some folks feel that they wish to be the arbiter of what is reasonable, and intend to "do it their way", whether the law agrees or not.

I PREFER lanes set aside for cyclists (bicycles, as in my link above), but this is not always possible.