"Refusing to Handle You"

So, an interesting thing happened today. I am at a fly-in at Hagerstown
and about to head back to my home-base at York (THV). I can see from
the PC they had there that there is a line of heavy rain and possibly
thunderstorms blocking my route back. There is no way around it to the
north, but there is a way to the south. So, instead of the usual
KHGR-SCAPE-THV to take me north of Camp David, I file a route via
HGR-MRB-EMI to so south and get in to York through the back door.
When I pick up my clearance, I am given the route via SCAPE, but I
"unable" that for weather, and they go away for a few minutes, and then
clear me as filed. I take off, and everything is fine, until I'm headed
southbound from the HGR VOR, when the Washington Center controller
calls me and says "Err, 8096J, Potomac Approach is refusing to handle
you, say intentions." So now, here I am, in the air with two small kids
on board, and being turned back towards what was, a while back at
least, some nasty weather. I ask for a hold at HGR to consider my
options, and luckily, by now the StormScope is showing the line has
dissipated. Now, I'm not happy, 'cos I know there's been cells
appearing along that route all PM, but I have little choice, so I take
the SCAPE route. All ends well, and we have an almost smooth ride, but
I was amazed that they gave me a clearance for that route, and then
wouldn't honor it! Comments???