What makes you say that they are easier? Are there more people who manages to solve a problem from ICPC than from IOI?
How do you compare those?
There were at least 2 very simple problems in IOI this year.
I haven't read the ICPC problem set, and perhaps there are some low-hanging fruits, but I highly doubt it.
Because I'm a ICPC medalist (not this year though) but not a IOI medalist.
Another evidence is that you only have 5 hours to solve 3 problems in IOI, but you need to solve 10+ problems in ICPC. It's impossible to have all 10+ problems to at IOI level in ICPC.