I think the reason why they not recommend the ICO as earning site because we all know it is risky, not full develop products or projects and some of the project are scam thats why we need to be vigilant and to be censorious.
That's true we know how risky is the cryptocurrency investment but as long we know how we manage it will be good, ICO is not good for earnings because it's not easy to know what is scam or not so better to make a deeply research before we invest or participate in any ICO.
I think ICO is the most riskier compared with other cryptocurrency investment, because it can takes a long time to get profit and also you never know is the ICO will scam or not, also is the team behind project will seriously do the project or not. I mean, you know, when a person got so much money, you will know the real attitude of the person is.