- How they decide what countries they are blocking?
They won't block a country if there's nothing wrong with that country's rule and status about crypto
- What's the difference between ICO's that block say 4 countries or more than 10 countries?
It's the devs preference on what countries to block and won't be allowed to invest to their project.
- Does this come into factor when i am investing in such projects?
If you are living in a country that doesn't have strict rule about crypto, you're fine.