Many ICO are scam but not 80%. many of them are failed to reach their target sale that I is why they have to declare as a failed ICO sale. It is not considered as scam because many failed ICO give back the investors money to avoid legal case that could bring them in jail.
I also think that most people on the forum confuse concepts and call everything scam, although initially a very small percentage of projects are released with the primary purpose of deceiving users. Most of them simply do not have an interesting idea and a strong team. These are just weak projects that are very easy to identify on a lot of different signs and just not have anything to do with them!