Totally agree with you. A quick look at the bitcointalk thread and a skim though the whitepaper will tell you much more than all those rating sites combined.
Not to mention that you can't trust those sources, they might just be paid to give a high score. That's why i like that the CEO did an interview on Youtube, where he passionately talks about the project. That is something you can trust.
Actually i always think they are getting paid for good scores but nevertheless, i like to check their scores. I don't know why but it is something to look at.
It's a big claim and i think that's wrong to think like this. Anyway I also check the ico ratings before investing, it has minor effect on my decisions but 1>0, so I think its something to look at before investments.
There are a lot of resources we can use to get better confidence including ICO's rating sites. We can combine it with other stuffs before we decided to invest our money.