It seems that some people are not happy with ISIS according to the article and the links below:

Pictures of Lebanese activists burning flags in Beruit in protest against Islamic State militants have sparked a hashtag campaign against Isis.
The hashtags #BurnISISFlagChallenge or #BurnISIS have been circulating across social media after pictures of three boys burning a flag in Beruit’s Sassine Square emerged on Saturday.
One example was a video of person burning a picture of the flag, captioned: “I nominate the whole world to the #BurnISISFlagChallenge. You have 24 hours. GO!!"
The burning is understood to be in response to the beheading of a Lebanese officer by Islamic militants. Photographs of the soldier's death were posted on social media on 28 August, prompting anger from mourners in Lebanon who accused the government of neglect for failing to secure his release.
The burning of the flag has been heavily criticised by the Lebanese justice minister, who was quoted in Lebanese news as warning the “strongest punishments” would be meted out to those who burned flags last week.

http://www.independent.co.uk/news/world/middle-east/isis-ice-bucket-challenge-lebanese-activists-burning-flag-sparks-antiislamic-state-hashtag-campaign-9714437.html

https://uk.news.yahoo.com/burn-isis-flag-challenge-goes-viral-arab-world-124824439.html#BEg7J8N

http://www.inquisitr.com/1454324/burn-isis-flag-challenge-going-viral-in-middle-east-as-anger-toward-militant-group-grows/