I think Hindus must avoid inviting congress men for attending Hindu Festival Functions. There are clear instructions in the Hindu scriptures for ignoring avoiding non-pious people in holy functions.
Although some people may argue that not all congress men are non-pious, but I am of the opinion if one has even remotely supported denigration of Ram or Krishna then one has to be considered non-pious. The congress is definitely guilty of denigration of Ram / Krishna in Setu Samudram episode.