I'd think German traffic engineers could come up with a better solution, yet these are everywhere:
The bike paths themselves are desire paths for cars and motorcycles.
To block them off, they put up barriers, but those also block cargo bikes, wheelchairs and strollers, create a collision hazard, and force all cyclists to stop and dismount for no reason.
Of course, they'll be bypassed wherever possible – naturally by cars and motorcycles too, if there's enough room.
Are the gates hinged so they can move back and forth, or are they stationary? If they are stationary they need some "saloon door" style hinges so they can swing back and forth, but default to the middle, blocking the path.
Also what do those blue signs mean?
They're stationary. The blue signs mean it's a combined bicycle and footpath.
They imply: banned for all motor vehicles, and if they're parallel to a road, bicycles must use them and not the road.
Hinges: some do, but they are typically locked with a key. The easiest would be bollards ("poller")
Blue sign means: pedestrians and bikes have to use this, and they share the path. If the line would be vertical, it would mean bikes/pedestrians have their own lanes