Defacing, destroying or removing items created by previous civilisations, occupiers, oppressors or opponents isn't new and has been going on ever since man could create objects to represent themselves. What is new now is that one portion of our society would really like to be included as equals and feels that symbols of past injustice and persecution would be better removed. In a similar way it's like living in Japan and having generals who ran the prisoner of war camps standing high above you or living in Germany and seeing statues of Hitler or Goebells. Bringing it closer to home we have a nice statue of Queen Victoria in Sydney. The Irish didn't want it, I wonder why, just part of their History i'n it?
Having said that I'm not sure where it will end as whenever you look at the foundations of the UK you sort of see how their wealth was gained, so it could be a long process.
Specifically on the Qatar WC, they should never have been awarded it.