After thirty years of living around and with the Gypsy Folk, I think that it is easy to take a little knowledge and miss the bigger picture.
There is nothing inherently wrong with the words Gypsy (capital G please) or Tinker or Traveller. It would be worthwhile to find out what each term means. Tinkers are a slang name given to the Rilantu Minciri, or Irish Travellers.
Gypsies are Romany's born to the life Diddecoi's or Poshrats are halfblood Gypsies and Travellers are those who have adopted the lifestyle.
All of this is a bit pedantic, and as long as you realise Gypsy folk don't mind being referred to as Travellers and do mind Travellers being referred to as Gypsies, please feel free to sing your heart out.
I'm not one for disrespecting McColl, but he did not really know half as much about the Gypsy life as he professed to. I think he took a lot of single opinions and believed them to be commonly held opinions. That said, I listened to Queen Caroline Hughes's niece sing Freeborn Man at Stowe Horse Fair. A great memory.