Nobody's saying the kids weren't in the wrong, daisy1679 (although as has been pointed out, they probably didn't get the subtlety of 'excuse me' meaning Hollanda wanted to get past, and they did sit down when asked to more specifically). What we are saying is that had she not been attempting to take the stroller down there, holding up all the people behind her in the process, and which isn't really the done thing, this exchange never would have needed to happen in the first place.
This just isn't the done thing in my neck of the woods. Perhaps in Hollanda's part of the country people wouldn't bat an eyelid at it, but here it would likely get you looked at a bit funny. Prams create all sorts of awful bottlenecks on the transport where I live (ever seen one on a rush hour bus?), which is why we have the 'fold up the stroller' rule, albeit sometimes unspoken.